refactor api issues load attributes for better performance (#1066)

routers/api/v1/repo/issue.go

@@ -40,13 +40,14 @@ func ListIssues(ctx *context.APIContext) {
 		issues = append(issues, tempIssues...)
 	}
 
-	// FIXME: use IssueList to improve performance.
-	apiIssues := make([]*api.Issue, len(issues))
-	for i := range issues {
-		if err = issues[i].LoadAttributes(); err != nil {
+	err = models.IssueList(issues).LoadAttributes()
+	if err != nil {
 		ctx.Error(500, "LoadAttributes", err)
 		return
 	}
+
+	apiIssues := make([]*api.Issue, len(issues))
+	for i := range issues {
 		apiIssues[i] = issues[i].APIFormat()
 	}