diff --git a/lib/models/user.js b/lib/models/user.js
index 286b5b98..1f0a0d00 100644
--- a/lib/models/user.js
+++ b/lib/models/user.js
@@ -15,7 +15,8 @@ var Model = require('../loopback').Model
   , DEFAULT_RESET_PW_TTL = 15 * 60 // 15 mins in seconds
   , DEFAULT_MAX_TTL = 31556926 // 1 year in seconds
   , Role = require('./role').Role
-  , ACL = require('./acl').ACL;
+  , ACL = require('./acl').ACL
+  , assert = require('assert');
 
 /**
  * Default User properties.