Limit scope on rails-jquery-autocomplete (rails3-jquery-autocomplete) gem - where clause issue - ruby-on-rails

Question

There is a recommended solution and it seems to work. The issue is in my where clause and I'm not sure what's wrong.
For reference, here is the solution(s):
https://stackoverflow.com/a/7250426/4379077
https://stackoverflow.com/a/7250341/4379077
I am trying to scope users that are members of the current_user's family tree memberships(branches) user's within my Nodes controller. This would normally be done using this code (current_user.family_tree.memberships).
Note I have successfully set this up to autocomplete showing all users (User.all):
In my routes:
resources :nodes do
get :autocomplete_user_first_name, :on => :collection
end
In my Node controller I have the following code:
autocomplete :user, :first_name, :extra_data => [:last_name, :email],
display_value: :full_name
And in my view I have the following form:
<%= form_for node do |f| %>
<%= f.label :user_tags %>
<%= f.autocomplete_field :user_tags, autocomplete_user_first_name_nodes_path, 'data-auto-focus' => true, value: nil %>
<%= f.submit %>
<% end %>
When I attempt to add the recommended solution to my nodes controller:
def get_autocomplete_items(parameters)
items = super(parameters)
items = items.where(:user_id => current_user.family_tree.memberships)
end
I get this message:
NoMethodError - super: no superclass method "get_autocomplete_items" for #<NodesController:0x007fc516692278>:
So, I found this article https://stackoverflow.com/a/18717327/4379077 and changed it to
def get_autocomplete_items(parameters)
items = active_record_get_autocomplete_items(parameters)
items = items.where(:user_id => current_user.family_tree.memberships)
end
It works, but I get the following error
PG::UndefinedColumn: ERROR: column users.user_id does not exist, so I changed the where clause to this :id => current_user.family_tree.memberships and I get this result
User Load (0.9ms) SELECT users.id, users.first_name, "users"."last_name",
"users"."email"
FROM "users" WHERE (LOWER(users.first_name) ILIKE 'mi%')
AND "users"."id" IN (SELECT "memberships"."id" FROM "memberships"
WHERE "memberships"."family_tree_id" = $1)
ORDER BY LOWER(users.first_name) ASC LIMIT 10 [["family_tree_id", 1]]
The issue is that I believe I need to get a collection within the membership model comparing the attribute membership.user_id to user.id. What am I doing wrong in my where clause?

Answer 1

Are Membership objects the same thing as Users?
if not, you need to get the user_id off the membership record
This line would need to change
# use pluck to get an array of user_ids.
items = items.where(:id => current_user.family_tree.memberships.pluck(:user_id))