Add postgres schema to the search_path on database connection (#12634)

Rather than rely on the user running the gitea server and db setting the
schema search_path correctly - if gitea is run with a schema we should
simply set the search_path to have that schema first in the path.

Fix #12505

Signed-off-by: Andrew Thornton <art27@cantab.net>

models/models.go

@@ -155,6 +155,16 @@ func getEngine() (*xorm.Engine, error) {
 		engine.Dialect().SetParams(map[string]string{"DEFAULT_VARCHAR": "nvarchar"})
 	}
 	engine.SetSchema(setting.Database.Schema)
+	if setting.Database.UsePostgreSQL && len(setting.Database.Schema) > 0 {
+		// Add the schema to the search path
+		if _, err := engine.Exec(`SELECT set_config(
+			'search_path',
+			? || ',' || current_setting('search_path'),
+			false)`,
+			setting.Database.Schema); err != nil {
+			return nil, err
+		}
+	}
 	return engine, nil
 }