Declare and lock all dependencies

* Remove custom gemfile usage;
* Move essential gems from custom gemfile to the standard one;
* Include bundler lock file in version control.

Gemfile

@@ -3,18 +3,26 @@ source 'https://rubygems.org'
 gem 'rails',  '~> 4.2.1'
 gem 'pg',     '~> 0.17'
 gem 'bcrypt', '~> 3.0'
+gem 'unicorn-rails'
 
 gem 'haml',   '~> 4.0'
 gem 'rabl',   '~> 0.6'
 
 
 group :development, :test do
+  gem 'pry-rails'
+end
+
+group :test do
   gem 'rspec-rails',        '~> 2.6'
   gem 'rspec-activemodel-mocks'
   gem 'spork',              github: 'tjouan/spork', branch: 'rspec-3'
   gem 'capybara',           '~> 2.2'
   gem 'factory_girl_rails', '~> 4.4'
   gem 'shoulda-matchers',   '~> 2.5'
-end
 
-eval File.read('Gemfile-custom.rb') if File.exist?('Gemfile-custom.rb')
+  gem 'rb-kqueue',      require: false
+  gem 'guard',          require: false
+  gem 'guard-rspec',    require: false
+  gem 'guard-spork',    require: false
+end