add special message 'No groups yet...'
add a '_groupPartial' partial template for a Group
You can now delete Groups /!\ still issues

/!\ A contact still shows a deleted group
You can now update a Group (its name)
minor UI changes related to saving a Group
You can now create new Groups
Edit a Group with a 'bootstrap/modal' + bootstrap v2.3.2
Create a Group with a 'bootstrap/modal'
let Emberjs create the recentContacts controller