diff --git a/lib/persistency/persistency.js b/lib/persistency/persistency.js
index e2fa31b..4b4696c 100644
--- a/lib/persistency/persistency.js
+++ b/lib/persistency/persistency.js
@@ -7,13 +7,19 @@ var FilePersistency = require('./file.js').Persistency;
 var MongoDBPersistency = require('./mongodb.js').Persistency;
 
 /**
- * @param {{uri: String, uri: String}} options
+ * @param {{uri: String, uri: String, persistenc}} options
  * @constructor
  */
 var Persistency = exports.Persistency = function(options) {
     var isMongoDbUri;
     var uri = options ? options.uri : null;
+    var implementation = options ? options.implementation : null;
 
+    if (implementation) {
+        this.implementation = implementation;
+        return;
+    }
+    
     if (uri) {
        isMongoDbUri = uri.indexOf('mongodb://') === 0;
        if (isMongoDbUri) {