Fix for users.groups response format

user groups should return a collection (not and object)

Request: /users/229/groups

Expected response:

{"metadata":{"count":7,"limit":100,"offset":0},"result":[{"groupId":70,"groupName":"PRO administration","groupState":1,"groupLDAP":0,"groupDescription":"Donne les droits de cr\u00e9ation de projet","userRightOnGroup":"AWR","isUserInShortGroupList":false,"links":null},{"groupId":142,"groupName":"Orange","groupState":1,"groupLDAP":0,"groupDescription":"Contains all users of this company : Wanadoo S.A.","userRightOnGroup":"R","isUserInShortGroupList":true,"links":null},{"groupId":1211,"groupName":"Hebex - Budgest - Administrateur","groupState":1,"groupLDAP":1,"groupDescription":"Hebex - Budgest - Administrateur","userRightOnGroup":"R","isUserInShortGroupList":true,"links":null},{"groupId":5701,"groupName":"Hebex - Gestion Budg\u00e9taire","groupState":1,"groupLDAP":1,"groupDescription":"Hebex - Gestion Budg\u00e9taire (5701)","userRightOnGroup":"R","isUserInShortGroupList":true,"links":null},{"groupId":5703,"groupName":"Hebex - Gestion Budg\u00e9taire - R\u00f4les - Administrateur","groupState":1,"groupLDAP":1,"groupDescription":"Hebex - Gestion Budg\u00e9taire - R\u00f4les - Administrateur","userRightOnGroup":"R","isUserInShortGroupList":true,"links":null},{"groupId":5811,"groupName":"Hebex - Surf","groupState":1,"groupLDAP":1,"groupDescription":"","userRightOnGroup":"R","isUserInShortGroupList":true,"links":null},{"groupId":5813,"groupName":"Hebex - Surf - R\u00f4les - Administrateur","groupState":1,"groupLDAP":1,"groupDescription":"","userRightOnGroup":"R","isUserInShortGroupList":true,"links":null}]}