Create new branch from branch selection dropdown (#2130)

* Create new branch from branch selection dropdown and rewrite it to VueJS

* Make updateLocalCopyToCommit as not exported

* Move branch name validation to model

* Fix possible race condition

modules/auth/repo_branch_form.go

@@ -0,0 +1,20 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package auth
+
+import (
+	"github.com/go-macaron/binding"
+	macaron "gopkg.in/macaron.v1"
+)
+
+// NewBranchForm form for creating a new branch
+type NewBranchForm struct {
+	NewBranchName string `binding:"Required;MaxSize(100);GitRefName"`
+}
+
+// Validate validates the fields
+func (f *NewBranchForm) Validate(ctx *macaron.Context, errs binding.Errors) binding.Errors {
+	return validate(errs, ctx.Data, f, ctx.Locale)
+}