Rewrite guides/rails from HAML to Markdown (#1046)

Signed-off-by: Takuya Noguchi <[email protected]>

source/guides/rails.html.md

@@ -0,0 +1,73 @@
+---
+title: How to use Bundler with Rails
+---
+
+Rails comes with baked in support with bundler.
+
+## How to use Bundler with Rails
+
+Install Rails as you normally would. Use sudo
+if you would normally use sudo to install gems.
+
+~~~
+$ gem install rails
+~~~
+
+We recommend using rvm for dependable Ruby
+installations, especially if you are switching
+between different versions of Ruby
+Generate a Rails app as usual
+
+~~~
+$ rails new myapp
+$ cd myapp
+~~~
+
+Run the server. Bundler is transparently managing
+your dependencies!
+
+~~~
+$ rails server
+~~~
+
+Add new dependencies to your Gemfile as you
+need them.
+
+~~~ruby
+gem 'nokogiri'
+gem 'geokit'
+~~~
+
+If you want a dependency to be loaded only in
+a certain Rails environment, place it in a group
+named after that Rails environment
+
+~~~ruby
+group :test do
+  gem 'rspec'
+  gem 'faker'
+end
+~~~
+
+You can place a dependency in multiple groups
+at once as well
+
+~~~ruby
+group :development, :test do
+  gem 'wirble'
+  gem 'ruby-debug'
+end
+~~~
+
+<a href="./groups.html" class="btn btn-primary">Learn More: Groups</a>
+
+After adding a dependency, if it is not yet
+installed, install it
+
+~~~
+$ bundle install
+~~~
+
+This will update all dependencies in your
+Gemfile to the latest versions that do not
+conflict with other dependencies