Remove duplicated dependencies

Gemfile

@@ -3,24 +3,9 @@ source "https://rubygems.org"
 gemspec
 
 group :development, :test, :production do
-  gem "jquery-rails"
   gem "quiet_assets"
-  gem "rails", ">= 4.0.0"
-  gem "slim"
-  gem "sqlite3"
-end
-
-group :test do
-  gem "rspec-rails", ">= 3.0.0"
 end
 
 group :development, :test do
   gem "pry-rails"
-  gem "thin"
-end
-
-group :assets do
-  gem "sass-rails"
-  gem "coffee-rails"
-  gem "uglifier"
 end