Move create/fork repository from models to modules/repository (#9489)

* Move create/fork repository from models to modules/repository

* fix wrong reference

* fix test

* fix test

* fix lint

* Fix DBContext

* remove duplicated TestMain

* fix lint

* fix conflicts

modules/repository/fork_test.go

@@ -0,0 +1,25 @@
+// 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 repository
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestForkRepository(t *testing.T) {
+	assert.NoError(t, models.PrepareTestDatabase())
+
+	// user 13 has already forked repo10
+	user := models.AssertExistsAndLoadBean(t, &models.User{ID: 13}).(*models.User)
+	repo := models.AssertExistsAndLoadBean(t, &models.Repository{ID: 10}).(*models.Repository)
+
+	fork, err := ForkRepository(user, user, repo, "test", "test")
+	assert.Nil(t, fork)
+	assert.Error(t, err)
+	assert.True(t, models.IsErrForkAlreadyExist(err))
+}