New command: HKEYS (Redis v2.0-dev).

lib/Predis.php

@@ -1234,6 +1234,8 @@ class RedisServer_vNext extends RedisServer_v1_2 {
                 'hashGet'               => '\Predis\Commands\HashGet',
             'hdel'                      => '\Predis\Commands\HashDelete',
                 'hashDelete'            => '\Predis\Commands\HashDelete',
+            'hkeys'                     => '\Predis\Commands\HashKeys',
+                'hashKeys'              => '\Predis\Commands\HashKeys',
         ));
     }
 }
@@ -1756,6 +1758,10 @@ class HashDelete extends \Predis\BulkCommand {
     public function getCommandId() { return 'HDEL'; }
 }
 
+class HashKeys extends \Predis\InlineCommand {
+    public function getCommandId() { return 'HKEYS'; }
+}
+
 /* multiple databases handling commands */
 class SelectDatabase extends \Predis\InlineCommand {
     public function canBeHashed()  { return false; }