fix dashboard 500 when no issues at all

- update locales
- update README

models/issue.go

@@ -410,6 +410,10 @@ func Issues(uid, assigneeID, repoID, posterID, milestoneID int64, repoIDs []int6
 	if repoID > 0 {
 		sess.Where("issue.repo_id=?", repoID).And("issue.is_closed=?", isClosed)
 	} else if repoIDs != nil {
+		// In case repository IDs are provided but actually no repository has issue.
+		if len(repoIDs) == 0 {
+			return make([]*Issue, 0), nil
+		}
 		sess.Where("issue.repo_id IN ("+strings.Join(base.Int64sToStrings(repoIDs), ",")+")").And("issue.is_closed=?", isClosed)
 	} else {
 		sess.Where("issue.is_closed=?", isClosed)