#controllers/tweets_controller.rb
def like
    @tweet.like.new(params[:user_id, :tweet_id])
    respond_to do |format|
      if @tweet.like.save
        format.html { redirect_to @tweet, notice: 'Like succeded.'}
        format.json { render :show, status: :ok, location: @tweet }
      else
        @tweet.like.destroy
        format.html { render :edit, notice: 'You dont like this anymore' }
        format.json { render json: @tweet.like.errors, status: :unprocessable_entity }
      end
    end
  end

#tweets/show.html.erb
<%= link_to 'Like', @tweet.like %>

#models/tweet.rb
class Tweet < ActiveRecord::Base
  belongs_to :user
  validates :text, presence: true, length: { maximum: 140 }
end

#models/like.rb
class Like < ActiveRecord::Base
  belongs_to :tweet
  belongs_to :user
  validates :user_id, presence: true
  validates :tweet_id, presence: true
end

#config/routes.rb
Rails.application.routes.draw do

  resources :tweets do
    resources :likes
  end

  resources :users
  root 'tweets#index'
end

#output
NoMethodError in Tweets#show
Showing /twitter/app/views/tweets/show.html.erb where line #14 raised:

undefined method `like' for #<Tweet:0x1648a4ad>