Simply update proposal & program_session together

RK fork allows speakers to update their proposal even after
program_session was created. Thus, we need to sync the contents when
a speaker updated their accepted proposal.

Author: amatsuda

app/controllers/proposals_controller.rb

@@ -108,6 +108,9 @@ def update
       @proposal.update(confirmed_at: Time.current)
       redirect_to [@event, @proposal], flash: {success: 'Thank you for confirming your participation'}
     elsif @proposal.speaker_update_and_notify(proposal_params)
+      if @proposal.program_session && ((@proposal.program_session.title != @proposal.title) || (@proposal.program_session.abstract != @proposal.abstract))
+        @proposal.program_session.update title: @proposal.title, abstract: @proposal.abstract
+      end
       redirect_to [@event, @proposal]
     else
       flash[:danger] = "There was a problem saving your proposal."

app/models/program_session.rb

@@ -73,14 +73,6 @@ class ProgramSession < ApplicationRecord
     where(session_format_id: session_format.id)
   end
 
-  def title
-    proposal&.title || super
-  end
-
-  def abstract
-    proposal&.abstract || super
-  end
-
   def self.create_from_proposal(proposal)
     self.transaction do
       ps = ProgramSession.create!(event_id: proposal.event_id,