Update user access level when adding to group.

app/models/group.rb

@@ -26,7 +26,8 @@ class Group < Namespace
 
   def add_users(user_ids, group_access)
     user_ids.compact.each do |user_id|
-      self.users_groups.create(user_id: user_id, group_access: group_access)
+      user = self.users_groups.find_or_initialize_by_user_id(user_id)
+      user.update_attributes(group_access: group_access)
     end
   end
 

spec/models/group_spec.rb

@@ -42,4 +42,16 @@ describe Group do
 
     it { group.users_groups.masters.map(&:user).should include(user) }
   end
+
+  describe :add_users do
+    let(:user) { create(:user) }
+    before { group.add_users([user.id], UsersGroup::GUEST) }
+
+    it "should update the group permission" do
+      group.users_groups.guests.map(&:user).should include(user)
+      group.add_users([user.id], UsersGroup::DEVELOPER)
+      group.users_groups.developers.map(&:user).should include(user)
+      group.users_groups.guests.map(&:user).should_not include(user)
+    end
+  end
 end