Add merge method constants (#410)

gitlab.go

@@ -213,6 +213,20 @@ const (
 	PublicVisibility   VisibilityValue = "public"
 )
 
+// MergeMethodValue represents a project merge type within GitLab.
+//
+// GitLab API docs: https://docs.gitlab.com/ce/api/projects.html#project-merge-method
+type MergeMethodValue string
+
+// List of available merge type
+//
+// GitLab API docs: https://docs.gitlab.com/ce/api/projects.html#project-merge-method
+const (
+	NoFastForwardMerge MergeMethodValue = "merge"
+	FastForwardMerge   MergeMethodValue = "ff"
+	RebaseMerge        MergeMethodValue = "rebase_merge"
+)
+
 // EventTypeValue represents actions type for contribution events
 type EventTypeValue string
 
@@ -830,3 +844,11 @@ func Visibility(v VisibilityValue) *VisibilityValue {
 	*p = v
 	return p
 }
+
+// MergeMethod is a helper routine that allocates a new MergeMethod
+// to sotre v and returns a pointer to it.
+func MergeMethod(v MergeMethodValue) *MergeMethodValue {
+	p := new(MergeMethodValue)
+	*p = v
+	return p
+}

projects.go

@@ -391,7 +391,7 @@ type CreateProjectOptions struct {
 	PublicJobs                                *bool             `url:"public_jobs,omitempty" json:"public_jobs,omitempty"`
 	OnlyAllowMergeIfPipelineSucceeds          *bool             `url:"only_allow_merge_if_pipeline_succeeds,omitempty" json:"only_allow_merge_if_pipeline_succeeds,omitempty"`
 	OnlyAllowMergeIfAllDiscussionsAreResolved *bool             `url:"only_allow_merge_if_all_discussions_are_resolved,omitempty" json:"only_allow_merge_if_all_discussions_are_resolved,omitempty"`
-	MergeMethod                               *string          `url:"merge_method,omitempty" json:"merge_method,omitempty"`
+	MergeMethod                               *MergeMethodValue `url:"merge_method,omitempty" json:"merge_method,omitempty"`
 	LFSEnabled                                *bool             `url:"lfs_enabled,omitempty" json:"lfs_enabled,omitempty"`
 	RequestAccessEnabled                      *bool             `url:"request_access_enabled,omitempty" json:"request_access_enabled,omitempty"`
 	TagList                                   *[]string         `url:"tag_list,omitempty" json:"tag_list,omitempty"`

projects_test.go

@@ -234,7 +234,10 @@ func TestCreateProject(t *testing.T) {
 		fmt.Fprint(w, `{"id":1}`)
 	})
 
-	opt := &CreateProjectOptions{Name: String("n")}
+	opt := &CreateProjectOptions{
+		Name:        String("n"),
+		MergeMethod: MergeMethod(RebaseMerge),
+	}
 
 	project, _, err := client.Projects.CreateProject(opt)
 	if err != nil {