Write a decorator

Gemfile

@@ -17,6 +17,7 @@ gem 'mini_magick'
 gem 'fog'
 gem 'stripe'
 gem 'figaro'
+gem 'draper'
 
 group :development do
   gem 'sqlite3'

Gemfile.lock

@@ -71,6 +71,11 @@ GEM
     database_cleaner (1.2.0)
     debug_inspector (0.0.2)
     diff-lcs (1.2.5)
+    draper (1.3.0)
+      actionpack (>= 3.0)
+      activemodel (>= 3.0)
+      activesupport (>= 3.0)
+      request_store (~> 1.0.3)
     erubis (2.7.0)
     eventmachine (1.0.0)
     excon (0.31.0)
@@ -159,6 +164,7 @@ GEM
     redis (3.0.7)
     redis-namespace (1.4.1)
       redis (~> 3.0.4)
+    request_store (1.0.5)
     rest-client (1.6.7)
       mime-types (>= 1.16)
     rspec-core (2.14.7)
@@ -251,6 +257,7 @@ DEPENDENCIES
   carrierwave
   coffee-rails
   database_cleaner
+  draper
   fabrication
   faker
   figaro

app/controllers/videos_controller.rb

@@ -7,7 +7,7 @@ def index
 	end
 
 	def show
-		@video = Video.find(params[:id])
+		@video = VideoDecorator.decorate(Video.find(params[:id]))
 		@reviews = @video.reviews
 	end
 

app/decorators/video_decorator.rb

@@ -0,0 +1,8 @@
+class VideoDecorator < Draper::Decorator
+
+	delegate_all
+
+	def rating
+		object.rating.present? ? "#{object.rating}/5.0" : "N/A"
+	end
+end

app/models/video.rb

@@ -10,4 +10,8 @@ def self.search_by_title(search_term)
 		return [] if search_term.blank?
 		where("title LIKE ?", "%#{search_term}%").order("created_at DESC")
 	end
+
+	def rating
+		reviews.average(:rating).round(1) if reviews.average(:rating)
+	end
 end

app/views/videos/show.html.haml

@@ -6,7 +6,8 @@
       .video_info.col-sm-3
         %header
           %h3 #{@video.title}
-          %span Rating: 4.5/5.0
+          %span Rating:
+          = @video.rating
         %p #{@video.description}
         .actions
           %a.btn.btn-primary(href="#{@video.video_url}") Watch Now