Prepare app for deployment to Heroku.

Gemfile

@@ -5,10 +5,13 @@ gem 'rails', '3.2.8'
 gem 'dynamic_form' # for form.error_messages
 gem 'pg'
 
-group :assets do
+group :assets, :production do
   gem 'sass-rails', '~> 3.2.3'
   gem 'coffee-rails', '~> 3.2.1'
   gem 'jquery-rails'
   gem 'uglifier', '>= 1.0.3'
 end
 
+group :production do
+  gem 'unicorn'
+end

Gemfile.lock

@@ -48,6 +48,7 @@ GEM
       railties (>= 3.1.0, < 5.0)
       thor (~> 0.14)
     json (1.7.5)
+    kgio (2.7.4)
     mail (2.4.4)
       i18n (>= 0.4.0)
       mime-types (~> 1.16)
@@ -78,6 +79,7 @@ GEM
       rake (>= 0.8.7)
       rdoc (~> 3.4)
       thor (>= 0.14.6, < 2.0)
+    raindrops (0.10.0)
     rake (0.9.2.2)
     rdoc (3.12)
       json (~> 1.4)
@@ -99,6 +101,10 @@ GEM
     uglifier (1.3.0)
       execjs (>= 0.3.0)
       multi_json (~> 1.0, >= 1.0.2)
+    unicorn (4.4.0)
+      kgio (~> 2.6)
+      rack
+      raindrops (~> 0.7)
 
 PLATFORMS
   ruby
@@ -111,3 +117,4 @@ DEPENDENCIES
   rails (= 3.2.8)
   sass-rails (~> 3.2.3)
   uglifier (>= 1.0.3)
+  unicorn

Procfile

@@ -0,0 +1 @@
+web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb

config/unicorn.rb

@@ -0,0 +1,2 @@
+worker_processes 4 # number of workers to spin up
+timeout 30 # restart workers that hang for 30 seconds