How do I increment or decrement an association field in ruby on rails -

some here folks: have 2 models (category, movie)that related this:

category has_many movies, movie belongs_to category

add_one belongs_to movie

add_one belongs_to :user

user has_many :add_one

movie has_many :add_one

i created table has 2 integer fields want increment , decrement depending on value of field.it has 2 other fields foreign keys. if clicked current user , value 1 should decrement 0 else 1. note: don't want use vote gem....i used on model want create have described here..any please.

create_table "add_one", force: :cascade |t| t.integer  "ineedone", default: 0, null:false t.integer "ineedonetoo", default: 0, null:false t.integer  "user_id" t.integer  "movie_id" end  routes: resources :category     resources :movies         member             put "addone" => "movies#toaddone"     end             end end 

in movie's show page did

link_to("add", toaddone_category_movie_path(@category, @movie, @user), method: :put) 

i created movie partial _movie.html

and loop through this:

<%category.movies.each |movie|%> <%=..........%> <%movie.add_ones.each |add|%> <%=add.ineedone%> end end 

the controller movie .

.....#before_action :find_category... before_action  :find_movie....etc  def toaddone @movie.add_one.each |add| add.increment!(:ineedone) add.create_activity :ineedone end 

.....

it runs , doesn't show error in server....but unfortunately when call add_one in rails console come out empty means nothing created , _movie partial shows nothing...please out please want show first before creating decrement action.