Add instagram background implementation and generalize application for other identity providers

app/assets/javascripts/supplier/app/models/user.js.coffee

@@ -1,14 +1,13 @@
 attr = DS.attr
 App.User= DS.Model.extend
-  facebook_id: attr('string')
-  email: attr('string')
   name: attr('string')
+  uid: attr('string')
+  provider: attr('string')
+  avatar: attr('string')
   list: DS.belongsTo('list') # in ember scope not many to many (yet)
   join_requests: DS.hasMany('join_request')
-  facebook_image_tag: (->
-    facebook_id = @get('facebook_id')
-    return '' unless facebook_id
-    url = "http://graph.facebook.com/#{facebook_id}/picture?type=square"
+  avatar_tag: (->
+    return unless avatar = @get('avatar')
     name = @get('name')
-    new Handlebars.SafeString "<img src=\"#{url}\" alt=\"#{name}\" title=\"#{name}\" class=\"user-facebook-image\">"
-  ).property('facebook_id', 'name')
+    "<img src='#{avatar}' alt='#{name}' title='#{name}' class='user-avatar-image #{@get('provider')}'>".htmlSafe()
+  ).property('avatar', 'name')

app/assets/javascripts/supplier/app/templates/_list_content.emblem

@@ -14,7 +14,7 @@ if list.closed_at
   .display-field= view "close-list-button" content=list
 .user-info-container
   each user in list.users
-    =user.facebook_image_tag
+    =user.avatar_tag
 if list.sorted_orders
   .list-orders-container
     each order in list.sorted_orders

app/assets/javascripts/supplier/app/templates/active_list.emblem

@@ -1,6 +1,6 @@
 td.user-info.show-for-large-up
   each user in view.content.users
-    =  user.facebook_image_tag
+    =  user.avatar_tag
 td.status-icons
   if view.content.needs_help
     span.icon.needs-help

app/assets/javascripts/supplier/app/templates/active_order.emblem

@@ -1,6 +1,6 @@
 td.user-info.show-for-large-up
   each user in view.content.list.users
-    =  user.facebook_image_tag
+    =  user.avatar_tag
 td.status-icons
   if view.content.active
     span.active-order.fa.fa-check.fa-lg

app/assets/javascripts/supplier/app/templates/orders_display.emblem

@@ -14,7 +14,7 @@ table.table
       tr
         td
           each user in order.list.users
-            =  user.facebook_image_tag
+            =  user.avatar_tag
         td.status-icons
           if order.active
             span.active-order.fa.fa-check.fa-lg

app/assets/javascripts/supplier/app/templates/section_table.emblem

@@ -18,7 +18,7 @@ if table.active_list
     /.table-action-row
       a{action "editTable" table}: span.fa.fa-lg.fa-wrench
     each user in table.active_list.users
-      = user.facebook_image_tag
+      = user.avatar_tag
 if editmodedisabled
   .table-settings
     select