Add venue_photos model and venue_photos admin controller in order to add more images to Venues and allow to delete it.

Show the additional photos in splash. Added fancybox gem for zoom when click on the additional photo.

fix #777

db/migrate/20160212231923_create_venue_photos.rb

@@ -0,0 +1,13 @@
+class CreateVenuePhotos < ActiveRecord::Migration
+  def change
+    create_table :venue_photos do |t|
+      t.integer :venue_id
+      t.string :photo_file_name
+      t.string :photo_content_type
+      t.integer :photo_file_size
+      t.datetime :photo_updated_at
+
+      t.timestamps null: false
+    end
+  end
+end