fix reference

git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@1094080 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/jquery.couch.js b/jquery.couch.js
index b5e9180..71ff6e9 100644
--- a/jquery.couch.js
+++ b/jquery.couch.js
@@ -183,7 +183,7 @@
     signup: function(user_doc, password, options) {
       options = options || {};
       // prepare user doc based on name and password
-      user_doc = prepareUserDoc(user_doc, password);
+      user_doc = this.prepareUserDoc(user_doc, password);
       $.couch.userDb(function(db) {
         db.saveDoc(user_doc, options);
       });