Merge branch 'master' of github.com:yii2mod/yii2-comments

Author: Igor Chepurnoy

.travis.yml

@@ -1,7 +1,6 @@
 language: php
 
 php:
-  - 5.5
   - 5.6
   - 7.0
 

models/CommentModel.php

@@ -336,7 +336,7 @@ public function getAvatar()
             return $this->author->getAvatar();
         }
 
-        return 'http://www.gravatar.com/avatar/00000000000000000000000000000000?d=mm&f=y&s=50';
+        return 'http://www.gravatar.com/avatar?d=mm&f=y&s=50';
     }
 
     /**
@@ -346,7 +346,16 @@ public function getAvatar()
      */
     public static function getAuthors()
     {
-        return ArrayHelper::map(static::find()->joinWith('author')->groupBy('createdBy')->asArray()->all(), 'createdBy', 'author.username');
+        $query = static::find()
+            ->alias('c')
+            ->select(['c.createdBy', 'a.username'])
+            ->joinWith('author a')
+            ->groupBy(['c.createdBy', 'a.username'])
+            ->orderBy('a.username')
+            ->asArray()
+            ->all();
+
+        return ArrayHelper::map($query, 'createdBy', 'author.username');
     }
 
     /**