issues comment API : list, create, edit (#2966)

add `since` query string support to list issue comment

models/issue_comment.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/Unknwon/com"
 	"github.com/go-xorm/xorm"
+	api "github.com/gogits/go-gogs-client"
 
 	"github.com/gogits/gogs/modules/log"
 	"github.com/gogits/gogs/modules/markdown"
@@ -104,6 +105,18 @@ func (c *Comment) AfterDelete() {
 	}
 }
 
+// APIFormat convert Comment struct to api.Comment struct
+func (c *Comment) APIFormat() *api.Comment {
+	apiComment := &api.Comment{
+		ID:      c.ID,
+		Poster:  c.Poster.APIFormat(),
+		Body:    c.Content,
+		Created: c.Created,
+	}
+
+	return apiComment
+}
+
 // HashTag returns unique hash tag for comment.
 func (c *Comment) HashTag() string {
 	return "issuecomment-" + com.ToStr(c.ID)