vrfs-310: added removed_music_session method, and after_destroy callback

lib/jam_ruby/models/music_session.rb

@@ -23,6 +23,10 @@ module JamRuby
 
     after_save :require_at_least_one_genre, :limit_max_genres
 
+    after_destroy do |obj|
+      JamRuby::MusicSessionHistory.removed_music_session(obj.user_id, obj.id)
+    end
+
     validates :description, :presence => true
     validates :fan_chat, :inclusion => {:in => [true, false]}
     validates :fan_access, :inclusion => {:in => [true, false]}

lib/jam_ruby/models/music_session_history.rb

@@ -56,5 +56,15 @@ module JamRuby
       session_history.genres = music_session.genres.map { |g| g.id }.join '|'
       session_history.save!
     end
+
+    def self.removed_music_session(user_id, session_id)
+      hist = self
+        .where(:user_id => user_id)
+        .where(:music_session_id => session_id)
+        .limit(1)
+        .first
+      hist.update_attribute(:session_removed_at, Time.now) if hist
+    end
+    
   end
-end
+end