Adding Gemfile.lock via bundle

From http://bundler.io/

Bundler maintains a consistent environment for ruby applications. It
tracks an application's code and the rubygems it needs to run, so that
an application will always have the exact gems (and versions) that it
needs to run.

aIf you were working on a gem, instead of an application, you would not
check-in your Gemfile.lock.

The following commands were run:
$ bundle
$ git add Gemfile.lock
Adding Devise 3.1.x to Gemfile

The `gem "devise", "~> 3.1.0"` declaration indicates that I only want
to use versions of Devise that are in the 3.1.x family.
I believe Devise is using to [semantic versioning](http://semver.org/)

Devise is a "Flexible authentication solution for Rails with Warden."
https://github.com/plataformatec/devise

Warden is a "General Rack Authentication Framework"
https://github.com/hassox/warden

Rack is "a modular Ruby webserver interface"
https://github.com/rack/rack
http://rack.github.io/
Bundling up Devise and its dependencies.

Among other things, Devise added the following dependencies to our
project.
    devise (3.1.0)
      bcrypt-ruby (~> 3.0)
      orm_adapter (~> 0.1)
      railties (>= 3.2.6, < 5)
      thread_safe (~> 0.1)
      warden (~> 1.2.3)

The following commands were run:
$ bundle
$ git add Gemfile.lock
Adding rspec-rails as a :test group dependency

From http://rspec.info/
RSpec is testing tool for the Ruby programming language. Born under
the banner of Behaviour-Driven Development, it is designed to make
Test-Driven Development a productive and enjoyable experience with
features like:

* a rich command line program (the rspec command)
* textual descriptions of examples and groups (rspec-core)
* flexible and customizable reporting
* extensible expectation language (rspec-expectations)
* built-in mocking/stubbing framework (rspec-mocks)

By declaring rspec-rails in the :test group, the gem is only available
when the application is running in test.