Add notification interface and refactor UI notifications (#5085)

* add notification interface and refactor UI notifications

* add missing methods on notification interface and notifiy only issue status really changed

* implement NotifyPullRequestReview for ui notification

models/issue.go

@@ -112,6 +112,10 @@ func (issue *Issue) GetPullRequest() (pr *PullRequest, err error) {
 	}
 
 	pr, err = getPullRequestByIssueID(x, issue.ID)
+	if err != nil {
+		return nil, err
+	}
+	pr.Issue = issue
 	return
 }
 

models/review.go

@@ -239,6 +239,8 @@ func getCurrentReview(e Engine, reviewer *User, issue *Issue) (*Review, error) {
 	if len(reviews) == 0 {
 		return nil, ErrReviewNotExist{}
 	}
+	reviews[0].Reviewer = reviewer
+	reviews[0].Issue = issue
 	return reviews[0], nil
 }