update MergePullRequest (#207)

update license header

code format

enforce enum

Fix #137

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Thomas Loubiou <xabufr@gmail.com>
Reviewed-by: Andrew Thornton <art27@cantab.net>
Reviewed-by: mrsdizzie <info@mrsdizzie.com>

gitea/pull.go

@@ -1,4 +1,5 @@
 // Copyright 2016 The Gogs Authors. All rights reserved.
+// Copyright 2019 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.
 
@@ -124,10 +125,28 @@ func (c *Client) EditPullRequest(owner, repo string, index int64, opt EditPullRe
 		jsonHeader, bytes.NewReader(body), pr)
 }
 
+// MergePullRequestOption options when merging a pull request
+type MergePullRequestOption struct {
+	// required: true
+	// enum: merge,rebase,rebase-merge,squash
+	Do                string `json:"Do" binding:"Required;In(merge,rebase,rebase-merge,squash)"`
+	MergeTitleField   string `json:"MergeTitleField"`
+	MergeMessageField string `json:"MergeMessageField"`
+}
+
+// MergePullRequestResponse response when merging a pull request
+type MergePullRequestResponse struct {
+}
+
 // MergePullRequest merge a PR to repository by PR id
-func (c *Client) MergePullRequest(owner, repo string, index int64) error {
-	_, err := c.getResponse("POST", fmt.Sprintf("/repos/%s/%s/pulls/%d/merge", owner, repo, index), nil, nil)
-	return err
+func (c *Client) MergePullRequest(owner, repo string, index int64, opt MergePullRequestOption) (*MergePullRequestResponse, error) {
+	body, err := json.Marshal(&opt)
+	if err != nil {
+		return nil, err
+	}
+	response := new(MergePullRequestResponse)
+	return response, c.getParsedResponse("POST", fmt.Sprintf("/repos/%s/%s/pulls/%d/merge", owner, repo, index),
+		jsonHeader, bytes.NewReader(body), response)
 }
 
 // IsPullRequestMerged test if one PR is merged to one repository