Push pre-release V4 Bootstrap-Sass gem

Created by: kkirsche

I think it'd be great to have a pre-release version released. Pre-release gems can be released as such:

Source: http://guides.rubygems.org/patterns/#prerelease-gems

Many gem developers have versions of their gem ready to go out for testing or “edge” releases before a big gem release. RubyGems supports the concept of “prerelease” versions, which could be betas, alphas, or anything else that isn’t ready as a regular release.

Taking advantage of this is easy. All you need is one or more letters in the gem version. For example, here’s what a prerelease gemspec’s version field might look like:

``` ruby`
Gem::Specification.new do |s| s.name = "bootstrap-sass" s.version = "4.0.0.alpha.1"


Other prerelease version numbers might include `2.0.0.rc1`, or `1.5.0.beta.3`. It just has to have a letter in it, and you’re set. These gems can then be installed with the `–pre` flag, like so:

``` shell
% gem list bootstrap-sass -r --pre

*** REMOTE GEMS ***

bootstrap-sass (4.0.0.alpha.1)

% gem install bootstrap-sass --pre
Successfully installed bootstrap-sass-4.0.0.alpha.1
1 gem installed