Modifying applications models so they're aware of eachother

board.rb

class Board < ActiveRecord::Base
  has_many :conversations
end

comment.rb

class Comment < ActiveRecord::Base
  belongs_to :conversation
  belongs_to :user
  validates_presence_of :body
end

conversation.rb

class Conversation < ActiveRecord::Base
  has_many :comments
  belongs_to :user
  belongs_to :board
  validates_presence_of :title
end