fixes & refactoring + possibility to easily publish to rubygems.org

That's nice little gem :)

I just fixed few things and refactored a bit in order to simplify installation & release to [rubygems.org](rubygems.org)

In order to publish it:
* bump version of the gem by changing lib/clouds/version.rb
* run `rake publish`

> In order to publish it you need to have account on [rubygems.org](rubygems.org). Here's [link to guide](http://guides.rubygems.org/publishing/#publishing_to_rubygemsorg).

> After creating the account, use your email and password when pushing the gem. 

> RubyGems saves the credentials in `~/.gem/credentials` for you so you only need to log in once.

Use rake task to publish:

    rake publish

Once gem is published, users can install it by typing:

    gem install clouds

or by adding dependency to the `Gemfile` like:

    gem 'clouds'


I have updated `README.md` and updated installation procedure to reflect changes.