Ruby on Rails

I'm still fairly new to RoR and am having a bit of trouble understanding how to setup the contributions controller and the form in the view.

Objective:
1. user1 creates post - which belongs to user1 
2. user2 click request button to join the user1_post as a contributor ( @ post_show page )

3. user1 clicks accepts or declines request button ( @ post_show page link_to contribution_requests ( true : false ) )
4. user2 is now a contributor to user1_post ( @ post_show list contributors )
5. user1 can remove user2 as a contributor ( @ post_show page link_to contribution_requests ( true : false ) )

Got the has_many :through setup properly and have tested it in the console

contribution.rb

class Contribution < ActiveRecord::Base    belongs_to :post    belongs_to :user      def accept      self.accepted = true    end  end

post.rb

class Post < ActiveRecord::Base    belongs_to :author, class_name: 'User'    has_many :contribution_requests, -> { where(accepted: false) }, class_name: 'Contribution'    has_many :contributions, -> { where(accepted: true) }    has_many :contributors, through: :contributions, source: :user  end

user.rb

class User < ActiveRecord::Base    has_many :posts, foreign_key: 'author_id'    has_many :contribution_requests, -> { where(accepted: false) }, class_name: 'Contribution'    has_many :contributions, -> { where(accepted: true) }    has_many :contributed_posts, through: :contributions, source: :post  end

#config/routes.rb  resources :posts do     resources :contributions, only: [:create, :destroy] #-> can use posts#edit to add extra contributions  end    #app/controllers/contributions_controller.rb  class ContributionsController < ApplicationController     def create        @post = Post.find params[:post_id]        @contribution = current_user.contributions.new contribution_params        @contribution.post = @post          notice = @contribution.save ? "Added Contributor" : "Unable to add contributor"        redirect_to @post, notice: notice     end       def destroy        @contribution = current_user.contributions.find params[:id]        @contribution.destroy          redirect_to root_url, notice: "Removed Contributor"  end       private       def contribution_params         params.require(:contribution).permit(:user, :post, :accepted)     end  end