Implement git refs API for listing references (branches, tags and other) (#5354)

* Inital routes to git refs api

* Git refs API implementation

* Update swagger

* Fix copyright

* Make swagger happy add basic test

* Fix test

* Fix test again :)

vendor/gopkg.in/src-d/go-git.v4/storage/storer.go

@@ -0,0 +1,26 @@
+package storage
+
+import (
+	"gopkg.in/src-d/go-git.v4/config"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
+)
+
+// Storer is a generic storage of objects, references and any information
+// related to a particular repository. The package gopkg.in/src-d/go-git.v4/storage
+// contains two implementation a filesystem base implementation (such as `.git`)
+// and a memory implementations being ephemeral
+type Storer interface {
+	storer.EncodedObjectStorer
+	storer.ReferenceStorer
+	storer.ShallowStorer
+	storer.IndexStorer
+	config.ConfigStorer
+	ModuleStorer
+}
+
+// ModuleStorer allows interact with the modules' Storers
+type ModuleStorer interface {
+	// Module returns a Storer representing a submodule, if not exists returns a
+	// new empty Storer is returned
+	Module(name string) (Storer, error)
+}