diff --git a/app/assets/javascripts/locomotive/models/membership.js.coffee b/app/assets/javascripts/locomotive/models/membership.js.coffee
index ef710c4d..35c59484 100644
--- a/app/assets/javascripts/locomotive/models/membership.js.coffee
+++ b/app/assets/javascripts/locomotive/models/membership.js.coffee
@@ -3,7 +3,7 @@ class Locomotive.Models.Membership extends Backbone.Model
   toJSONForSave: ->
     _.tap {}, (hash) =>
       for key, value of @.toJSON()
-        hash[key] = value if _.include(['id', 'role', '_destroy'], key)
+        hash[key] = value if _.include(['id', '_id', 'role', '_destroy'], key)
 
 class Locomotive.Models.MembershipsCollection extends Backbone.Collection
 
diff --git a/app/assets/javascripts/locomotive/models/site.js.coffee b/app/assets/javascripts/locomotive/models/site.js.coffee
index b0af198f..80173934 100644
--- a/app/assets/javascripts/locomotive/models/site.js.coffee
+++ b/app/assets/javascripts/locomotive/models/site.js.coffee
@@ -21,7 +21,8 @@ class Locomotive.Models.Site extends Backbone.Model
 
   toJSON: ->
     _.tap super, (hash) =>
-      hash.memberships = @get('memberships').toJSONForSave() if @get('memberships')
+      delete hash.memberships
+      hash.memberships_attributes = @get('memberships').toJSONForSave() if @get('memberships')? && @get('memberships').length > 0
       hash.domains = _.map(@get('domains'), (domain) -> domain.get('name'))
 
 class Locomotive.Models.CurrentSite extends Locomotive.Models.Site
diff --git a/doc/TODO b/doc/TODO
index c37743c9..b786d330 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -104,18 +104,23 @@ x deployment
     x data ?
 x script to migrate existing site
   x i18n
+- upgrade to rails 3.2 (https://github.com/locomotivecms/engine/pull/281/files)
+- missing custom_fields
+  x belongs_to
+  - has_many
+  - many_to_many
 - heroku module for locomotive
 - refactoring
   x remove the import / export scripts
   x remove the cross domain authentication (use auth_token instead)
   - where to put Locomotive::InlineEditorMiddleware ?
-- upgrade to rails 3.2 (https://github.com/locomotivecms/engine/pull/281/files)
 
 - bugs / ui tweaks
   x unable to toggle the "required" check_boxes for content types
   x unable to sign out
   x unable to remove a field
   x "back to admin" link does not work if inline editor disabled
+  x unable to delete memberships
   - display by categories does not work when localized
   - disallow to click twice on the submit form button (spinner ?)
   - message to notify people if their browser is too old