stores a proposal notification

app/models/proposal_notification.rb

@@ -0,0 +1,8 @@
+class ProposalNotification < ActiveRecord::Base
+  belongs_to :author, class_name: 'User', foreign_key: 'author_id'
+  belongs_to :proposal
+
+  validates :title, presence: true
+  validates :body, presence: true
+  validates :proposal, presence: true
+end