Fix Rails Gem CanCan bug for ActiveModel::ForbiddenAttributesError - ruby-on-rails

Question

When attempting to create on a model with CanCan set as manage: all I am continuously getting this error:
ActiveModel::ForbiddenAttributesError - ActiveModel::ForbiddenAttributesError:
I found a fix online here.
That pastes this code into my applications controller:
before_filter do
resource = controller_name.singularize.to_sym
method = "#{resource}_params"
params[resource] &&= send(method) if respond_to?(method, true)
end
This leads to my issue. I have two models with belongs_to_has_many association and a method that adds an user to a group.
When I want to add an user to a group using add_user which takes the group id and the user object I now get this error.
The routine is called by:
<%= link_to 'Add', add_user_group_path(group: #group, user_id: id) %>
The method looks like this:
def add_user
group = Group.find(params[:id])
user = User.find(params[:user_id])
group.users << user
end
And this is the error:
Parameters: {"group"=>"16", "id"=>"16", "user_id"=>"332"}
NoMethodError - undefined method `permit' for "16":String:
What is the before_filter method doing that would cause this error?
================ UPDATE ===================
I ended up figuring it out.
Since the group id is automatically passed in the add_user call from the controller I had to change this line:
<%= link_to 'Add', add_user_group_path(group: #group, user_id: id) %>
to:
<%= link_to 'Add', add_user_group_path(user_id: id) %>
And it now works. Turns out when you pass the #group object the param "group => x" gets parsed weird.

Answer 1

CanCan is not working with Rails4. Use CanCanCan, and you don't need any of these workaround. Just have some following methods just like what we normally do in Rails4.
create_params or update_params (depending on the action you are performing)
_params such as article_params (this is the
default convention in rails for naming your param method)
resource_params (a generically named method you could specify in each
controller)
Link Here: https://github.com/CanCanCommunity/cancancan