Allow Gogs to run from a suburl behind a reverse proxy. e.g. http://mydomain.com/gogs/

Conflicts:
	modules/setting/setting.go

Conflicts:
	templates/repo/release/list.tmpl
	templates/user/dashboard/dashboard.tmpl

Conflicts:
	routers/repo/setting.go

routers/admin/admin.go

@@ -143,7 +143,7 @@ func Dashboard(ctx *middleware.Context) {
 		} else {
 			ctx.Flash.Success(success)
 		}
-		ctx.Redirect("/admin")
+		ctx.Redirect(setting.AppRootSubUrl + "/admin")
 		return
 	}