diff --git a/models/error.go b/models/error.go
index 459954545a..cafe11a154 100644
--- a/models/error.go
+++ b/models/error.go
@@ -8,10 +8,12 @@ import (
 	"fmt"
 )
 
+// ErrNameReserved ...
 type ErrNameReserved struct {
 	Name string
 }
 
+// IsErrNameReserved ...
 func IsErrNameReserved(err error) bool {
 	_, ok := err.(ErrNameReserved)
 	return ok
@@ -21,10 +23,12 @@ func (err ErrNameReserved) Error() string {
 	return fmt.Sprintf("name is reserved [name: %s]", err.Name)
 }
 
+// ErrNamePatternNotAllowed ...
 type ErrNamePatternNotAllowed struct {
 	Pattern string
 }
 
+// IsErrNamePatternNotAllowed ...
 func IsErrNamePatternNotAllowed(err error) bool {
 	_, ok := err.(ErrNamePatternNotAllowed)
 	return ok
@@ -41,10 +45,12 @@ func (err ErrNamePatternNotAllowed) Error() string {
 // |______//____  >\___  >__|
 //              \/     \/
 
+// ErrUserAlreadyExist ...
 type ErrUserAlreadyExist struct {
 	Name string
 }
 
+// IsErrUserAlreadyExist ...
 func IsErrUserAlreadyExist(err error) bool {
 	_, ok := err.(ErrUserAlreadyExist)
 	return ok
@@ -54,12 +60,14 @@ func (err ErrUserAlreadyExist) Error() string {
 	return fmt.Sprintf("user already exists [name: %s]", err.Name)
 }
 
+// ErrUserNotExist ...
 type ErrUserNotExist struct {
 	UID   int64
 	Name  string
 	KeyID int64
 }
 
+// IsErrUserNotExist ...
 func IsErrUserNotExist(err error) bool {
 	_, ok := err.(ErrUserNotExist)
 	return ok
@@ -69,10 +77,12 @@ func (err ErrUserNotExist) Error() string {
 	return fmt.Sprintf("user does not exist [uid: %d, name: %s, keyid: %d]", err.UID, err.Name, err.KeyID)
 }
 
+// ErrEmailAlreadyUsed ...
 type ErrEmailAlreadyUsed struct {
 	Email string
 }
 
+// IsErrEmailAlreadyUsed ...
 func IsErrEmailAlreadyUsed(err error) bool {
 	_, ok := err.(ErrEmailAlreadyUsed)
 	return ok
@@ -82,10 +92,12 @@ func (err ErrEmailAlreadyUsed) Error() string {
 	return fmt.Sprintf("e-mail has been used [email: %s]", err.Email)
 }
 
+// ErrUserOwnRepos ...
 type ErrUserOwnRepos struct {
 	UID int64
 }
 
+// IsErrUserOwnRepos ...
 func IsErrUserOwnRepos(err error) bool {
 	_, ok := err.(ErrUserOwnRepos)
 	return ok
@@ -95,10 +107,12 @@ func (err ErrUserOwnRepos) Error() string {
 	return fmt.Sprintf("user still has ownership of repositories [uid: %d]", err.UID)
 }
 
+// ErrUserHasOrgs ...
 type ErrUserHasOrgs struct {
 	UID int64
 }
 
+// IsErrUserHasOrgs ...
 func IsErrUserHasOrgs(err error) bool {
 	_, ok := err.(ErrUserHasOrgs)
 	return ok
@@ -108,10 +122,12 @@ func (err ErrUserHasOrgs) Error() string {
 	return fmt.Sprintf("user still has membership of organizations [uid: %d]", err.UID)
 }
 
+// ErrReachLimitOfRepo ...
 type ErrReachLimitOfRepo struct {
 	Limit int
 }
 
+// IsErrReachLimitOfRepo ...
 func IsErrReachLimitOfRepo(err error) bool {
 	_, ok := err.(ErrReachLimitOfRepo)
 	return ok
@@ -128,10 +144,12 @@ func (err ErrReachLimitOfRepo) Error() string {
 //   \__/\  / |__|__|_ \__|
 //        \/          \/
 
+// ErrWikiAlreadyExist ...
 type ErrWikiAlreadyExist struct {
 	Title string
 }
 
+// IsErrWikiAlreadyExist ...
 func IsErrWikiAlreadyExist(err error) bool {
 	_, ok := err.(ErrWikiAlreadyExist)
 	return ok
@@ -148,10 +166,12 @@ func (err ErrWikiAlreadyExist) Error() string {
 //  |____|   |____/|___  /____/__|\___  > |____|__ \___  > ____|
 //                     \/             \/          \/   \/\/
 
+// ErrKeyUnableVerify ...
 type ErrKeyUnableVerify struct {
 	Result string
 }
 
+// IsErrKeyUnableVerify ...
 func IsErrKeyUnableVerify(err error) bool {
 	_, ok := err.(ErrKeyUnableVerify)
 	return ok
@@ -161,10 +181,12 @@ func (err ErrKeyUnableVerify) Error() string {
 	return fmt.Sprintf("Unable to verify key content [result: %s]", err.Result)
 }
 
+// ErrKeyNotExist ...
 type ErrKeyNotExist struct {
 	ID int64
 }
 
+// IsErrKeyNotExist ...
 func IsErrKeyNotExist(err error) bool {
 	_, ok := err.(ErrKeyNotExist)
 	return ok
@@ -174,11 +196,13 @@ func (err ErrKeyNotExist) Error() string {
 	return fmt.Sprintf("public key does not exist [id: %d]", err.ID)
 }
 
+// ErrKeyAlreadyExist ...
 type ErrKeyAlreadyExist struct {
 	OwnerID int64
 	Content string
 }
 
+// IsErrKeyAlreadyExist ...
 func IsErrKeyAlreadyExist(err error) bool {
 	_, ok := err.(ErrKeyAlreadyExist)
 	return ok
@@ -188,11 +212,13 @@ func (err ErrKeyAlreadyExist) Error() string {
 	return fmt.Sprintf("public key already exists [owner_id: %d, content: %s]", err.OwnerID, err.Content)
 }
 
+// ErrKeyNameAlreadyUsed ...
 type ErrKeyNameAlreadyUsed struct {
 	OwnerID int64
 	Name    string
 }
 
+// IsErrKeyNameAlreadyUsed ...
 func IsErrKeyNameAlreadyUsed(err error) bool {
 	_, ok := err.(ErrKeyNameAlreadyUsed)
 	return ok
@@ -202,12 +228,14 @@ func (err ErrKeyNameAlreadyUsed) Error() string {
 	return fmt.Sprintf("public key already exists [owner_id: %d, name: %s]", err.OwnerID, err.Name)
 }
 
+// ErrKeyAccessDenied ...
 type ErrKeyAccessDenied struct {
 	UserID int64
 	KeyID  int64
 	Note   string
 }
 
+// IsErrKeyAccessDenied ...
 func IsErrKeyAccessDenied(err error) bool {
 	_, ok := err.(ErrKeyAccessDenied)
 	return ok
@@ -218,12 +246,14 @@ func (err ErrKeyAccessDenied) Error() string {
 		err.UserID, err.KeyID, err.Note)
 }
 
+// ErrDeployKeyNotExist ...
 type ErrDeployKeyNotExist struct {
 	ID     int64
 	KeyID  int64
 	RepoID int64
 }
 
+// IsErrDeployKeyNotExist ...
 func IsErrDeployKeyNotExist(err error) bool {
 	_, ok := err.(ErrDeployKeyNotExist)
 	return ok
@@ -233,11 +263,13 @@ func (err ErrDeployKeyNotExist) Error() string {
 	return fmt.Sprintf("Deploy key does not exist [id: %d, key_id: %d, repo_id: %d]", err.ID, err.KeyID, err.RepoID)
 }
 
+// ErrDeployKeyAlreadyExist ...
 type ErrDeployKeyAlreadyExist struct {
 	KeyID  int64
 	RepoID int64
 }
 
+// IsErrDeployKeyAlreadyExist ...
 func IsErrDeployKeyAlreadyExist(err error) bool {
 	_, ok := err.(ErrDeployKeyAlreadyExist)
 	return ok
@@ -247,11 +279,13 @@ func (err ErrDeployKeyAlreadyExist) Error() string {
 	return fmt.Sprintf("public key already exists [key_id: %d, repo_id: %d]", err.KeyID, err.RepoID)
 }
 
+// ErrDeployKeyNameAlreadyUsed ...
 type ErrDeployKeyNameAlreadyUsed struct {
 	RepoID int64
 	Name   string
 }
 
+// IsErrDeployKeyNameAlreadyUsed ...
 func IsErrDeployKeyNameAlreadyUsed(err error) bool {
 	_, ok := err.(ErrDeployKeyNameAlreadyUsed)
 	return ok
@@ -268,10 +302,12 @@ func (err ErrDeployKeyNameAlreadyUsed) Error() string {
 // \____|__  /\___  >___  >___  >____  >____  > |____| \____/|__|_ \\___  >___|  /
 //         \/     \/    \/    \/     \/     \/                    \/    \/     \/
 
+// ErrAccessTokenNotExist ...
 type ErrAccessTokenNotExist struct {
 	SHA string
 }
 
+// IsErrAccessTokenNotExist ...
 func IsErrAccessTokenNotExist(err error) bool {
 	_, ok := err.(ErrAccessTokenNotExist)
 	return ok
@@ -281,9 +317,11 @@ func (err ErrAccessTokenNotExist) Error() string {
 	return fmt.Sprintf("access token does not exist [sha: %s]", err.SHA)
 }
 
+// ErrAccessTokenEmpty ...
 type ErrAccessTokenEmpty struct {
 }
 
+// IsErrAccessTokenEmpty ...
 func IsErrAccessTokenEmpty(err error) bool {
 	_, ok := err.(ErrAccessTokenEmpty)
 	return ok
@@ -300,10 +338,12 @@ func (err ErrAccessTokenEmpty) Error() string {
 // \_______  /__|  \___  (____  /___|  /__/_____ \(____  /__| |__|\____/|___|  /
 //         \/     /_____/     \/     \/         \/     \/                    \/
 
+// ErrLastOrgOwner ...
 type ErrLastOrgOwner struct {
 	UID int64
 }
 
+// IsErrLastOrgOwner ...
 func IsErrLastOrgOwner(err error) bool {
 	_, ok := err.(ErrLastOrgOwner)
 	return ok
@@ -320,12 +360,14 @@ func (err ErrLastOrgOwner) Error() string {
 //  |____|_  /\___  >   __/ \____/____  >__||__|  \____/|__|   / ____|
 //         \/     \/|__|              \/                       \/
 
+// ErrRepoNotExist ...
 type ErrRepoNotExist struct {
 	ID   int64
 	UID  int64
 	Name string
 }
 
+// IsErrRepoNotExist ...
 func IsErrRepoNotExist(err error) bool {
 	_, ok := err.(ErrRepoNotExist)
 	return ok
@@ -335,11 +377,13 @@ func (err ErrRepoNotExist) Error() string {
 	return fmt.Sprintf("repository does not exist [id: %d, uid: %d, name: %s]", err.ID, err.UID, err.Name)
 }
 
+// ErrRepoAlreadyExist ...
 type ErrRepoAlreadyExist struct {
 	Uname string
 	Name  string
 }
 
+// IsErrRepoAlreadyExist ...
 func IsErrRepoAlreadyExist(err error) bool {
 	_, ok := err.(ErrRepoAlreadyExist)
 	return ok
@@ -349,12 +393,14 @@ func (err ErrRepoAlreadyExist) Error() string {
 	return fmt.Sprintf("repository already exists [uname: %s, name: %s]", err.Uname, err.Name)
 }
 
+// ErrInvalidCloneAddr ...
 type ErrInvalidCloneAddr struct {
 	IsURLError         bool
 	IsInvalidPath      bool
 	IsPermissionDenied bool
 }
 
+// IsErrInvalidCloneAddr ...
 func IsErrInvalidCloneAddr(err error) bool {
 	_, ok := err.(ErrInvalidCloneAddr)
 	return ok
@@ -365,10 +411,12 @@ func (err ErrInvalidCloneAddr) Error() string {
 		err.IsURLError, err.IsInvalidPath, err.IsPermissionDenied)
 }
 
+// ErrUpdateTaskNotExist ...
 type ErrUpdateTaskNotExist struct {
 	UUID string
 }
 
+// IsErrUpdateTaskNotExist ...
 func IsErrUpdateTaskNotExist(err error) bool {
 	_, ok := err.(ErrUpdateTaskNotExist)
 	return ok
@@ -378,10 +426,12 @@ func (err ErrUpdateTaskNotExist) Error() string {
 	return fmt.Sprintf("update task does not exist [uuid: %s]", err.UUID)
 }
 
+// ErrReleaseAlreadyExist ...
 type ErrReleaseAlreadyExist struct {
 	TagName string
 }
 
+// IsErrReleaseAlreadyExist ...
 func IsErrReleaseAlreadyExist(err error) bool {
 	_, ok := err.(ErrReleaseAlreadyExist)
 	return ok
@@ -391,11 +441,13 @@ func (err ErrReleaseAlreadyExist) Error() string {
 	return fmt.Sprintf("release tag already exist [tag_name: %s]", err.TagName)
 }
 
+// ErrReleaseNotExist ...
 type ErrReleaseNotExist struct {
 	ID      int64
 	TagName string
 }
 
+// IsErrReleaseNotExist ...
 func IsErrReleaseNotExist(err error) bool {
 	_, ok := err.(ErrReleaseNotExist)
 	return ok
@@ -405,10 +457,12 @@ func (err ErrReleaseNotExist) Error() string {
 	return fmt.Sprintf("release tag does not exist [id: %d, tag_name: %s]", err.ID, err.TagName)
 }
 
+// ErrInvalidTagName ...
 type ErrInvalidTagName struct {
 	TagName string
 }
 
+// IsErrInvalidTagName ...
 func IsErrInvalidTagName(err error) bool {
 	_, ok := err.(ErrInvalidTagName)
 	return ok
@@ -418,10 +472,12 @@ func (err ErrInvalidTagName) Error() string {
 	return fmt.Sprintf("release tag name is not valid [tag_name: %s]", err.TagName)
 }
 
+// ErrRepoFileAlreadyExist ...
 type ErrRepoFileAlreadyExist struct {
 	FileName string
 }
 
+// IsErrRepoFileAlreadyExist ...
 func IsErrRepoFileAlreadyExist(err error) bool {
 	_, ok := err.(ErrRepoFileAlreadyExist)
 	return ok
@@ -438,10 +494,12 @@ func (err ErrRepoFileAlreadyExist) Error() string {
 //  |______  / |__|  (____  /___|  /\___  >___|  /
 //         \/             \/     \/     \/     \/
 
+// ErrBranchNotExist ...
 type ErrBranchNotExist struct {
 	Name string
 }
 
+// IsErrBranchNotExist ...
 func IsErrBranchNotExist(err error) bool {
 	_, ok := err.(ErrBranchNotExist)
 	return ok
@@ -458,10 +516,12 @@ func (err ErrBranchNotExist) Error() string {
 //   \__/\  /  \___  >___  /___|  /\____/ \____/|__|_ \
 //        \/       \/    \/     \/                   \/
 
+// ErrWebhookNotExist ...
 type ErrWebhookNotExist struct {
 	ID int64
 }
 
+// IsErrWebhookNotExist ...
 func IsErrWebhookNotExist(err error) bool {
 	_, ok := err.(ErrWebhookNotExist)
 	return ok
@@ -478,12 +538,14 @@ func (err ErrWebhookNotExist) Error() string {
 // |___/____  >____  >____/  \___  >
 //          \/     \/            \/
 
+// ErrIssueNotExist ...
 type ErrIssueNotExist struct {
 	ID     int64
 	RepoID int64
 	Index  int64
 }
 
+// IsErrIssueNotExist ...
 func IsErrIssueNotExist(err error) bool {
 	_, ok := err.(ErrIssueNotExist)
 	return ok
@@ -500,6 +562,7 @@ func (err ErrIssueNotExist) Error() string {
 //  |____|   |____/|____/____/____|_  /\___  >__   |____/  \___  >____  > |__|
 //                                  \/     \/   |__|           \/     \/
 
+// ErrPullRequestNotExist ...
 type ErrPullRequestNotExist struct {
 	ID         int64
 	IssueID    int64
@@ -509,6 +572,7 @@ type ErrPullRequestNotExist struct {
 	BaseBranch string
 }
 
+// IsErrPullRequestNotExist ...
 func IsErrPullRequestNotExist(err error) bool {
 	_, ok := err.(ErrPullRequestNotExist)
 	return ok
@@ -526,11 +590,13 @@ func (err ErrPullRequestNotExist) Error() string {
 //  \______  /\____/|__|_|  /__|_|  /\___  >___|  /__|
 //         \/             \/      \/     \/     \/
 
+// ErrCommentNotExist ...
 type ErrCommentNotExist struct {
 	ID      int64
 	IssueID int64
 }
 
+// IsErrCommentNotExist ...
 func IsErrCommentNotExist(err error) bool {
 	_, ok := err.(ErrCommentNotExist)
 	return ok
@@ -547,11 +613,13 @@ func (err ErrCommentNotExist) Error() string {
 // |_______ (____  /___  /\___  >____/
 //         \/    \/    \/     \/
 
+// ErrLabelNotExist ...
 type ErrLabelNotExist struct {
 	LabelID int64
 	RepoID  int64
 }
 
+// IsErrLabelNotExist ...
 func IsErrLabelNotExist(err error) bool {
 	_, ok := err.(ErrLabelNotExist)
 	return ok
@@ -568,11 +636,13 @@ func (err ErrLabelNotExist) Error() string {
 // \____|__  /__|____/\___  >____  > |__|  \____/|___|  /\___  >
 //         \/             \/     \/                   \/     \/
 
+// ErrMilestoneNotExist ...
 type ErrMilestoneNotExist struct {
 	ID     int64
 	RepoID int64
 }
 
+// IsErrMilestoneNotExist ...
 func IsErrMilestoneNotExist(err error) bool {
 	_, ok := err.(ErrMilestoneNotExist)
 	return ok
@@ -589,11 +659,13 @@ func (err ErrMilestoneNotExist) Error() string {
 // \____|__  /__|  |__| (____  /\___  >___|  /__|_|  /\___  >___|  /__|
 //         \/                \/     \/     \/      \/     \/     \/
 
+// ErrAttachmentNotExist ...
 type ErrAttachmentNotExist struct {
 	ID   int64
 	UUID string
 }
 
+// IsErrAttachmentNotExist ...
 func IsErrAttachmentNotExist(err error) bool {
 	_, ok := err.(ErrAttachmentNotExist)
 	return ok
@@ -610,10 +682,12 @@ func (err ErrAttachmentNotExist) Error() string {
 // |_______ \____/\___  /|__|___|  / /_______  /\____/|____/ |__|    \___  >___  >
 //         \/    /_____/         \/          \/                          \/    \/
 
+// ErrLoginSourceNotExist ...
 type ErrLoginSourceNotExist struct {
 	ID int64
 }
 
+// IsErrLoginSourceNotExist ...
 func IsErrLoginSourceNotExist(err error) bool {
 	_, ok := err.(ErrLoginSourceNotExist)
 	return ok
@@ -623,10 +697,12 @@ func (err ErrLoginSourceNotExist) Error() string {
 	return fmt.Sprintf("login source does not exist [id: %d]", err.ID)
 }
 
+// ErrLoginSourceAlreadyExist ...
 type ErrLoginSourceAlreadyExist struct {
 	Name string
 }
 
+// IsErrLoginSourceAlreadyExist ...
 func IsErrLoginSourceAlreadyExist(err error) bool {
 	_, ok := err.(ErrLoginSourceAlreadyExist)
 	return ok
@@ -636,10 +712,12 @@ func (err ErrLoginSourceAlreadyExist) Error() string {
 	return fmt.Sprintf("login source already exists [name: %s]", err.Name)
 }
 
+// ErrLoginSourceInUse ...
 type ErrLoginSourceInUse struct {
 	ID int64
 }
 
+// IsErrLoginSourceInUse ...
 func IsErrLoginSourceInUse(err error) bool {
 	_, ok := err.(ErrLoginSourceInUse)
 	return ok
@@ -656,11 +734,13 @@ func (err ErrLoginSourceInUse) Error() string {
 //   |____| \___  >____  /__|_|  /
 //              \/     \/      \/
 
+// ErrTeamAlreadyExist ...
 type ErrTeamAlreadyExist struct {
 	OrgID int64
 	Name  string
 }
 
+// IsErrTeamAlreadyExist ...
 func IsErrTeamAlreadyExist(err error) bool {
 	_, ok := err.(ErrTeamAlreadyExist)
 	return ok
@@ -678,11 +758,13 @@ func (err ErrTeamAlreadyExist) Error() string {
 //           |__|                   \/      \/
 //
 
+// ErrUploadNotExist ...
 type ErrUploadNotExist struct {
 	ID   int64
 	UUID string
 }
 
+// IsErrUploadNotExist ...
 func IsErrUploadNotExist(err error) bool {
 	_, ok := err.(ErrAttachmentNotExist)
 	return ok