Use `rhc cartridge add`

`rhc app cartridge add` is deprecated.
Merge pull request #14 from jroes/patch-1

Use `rhc cartridge add`
Update 'rhc cartridge' command usage
Persistent Rails assets
fixing a couple of typos
Merge pull request #16 from developercorey/master

Fixed a couple of typos
Update to Rails 3.2.12, and explicity require rack 1.4.5 (which is not strictly required)
Merge pull request #17 from BanzaiMan/rails_3.2.12

Update to Rails 3.2.12
One more occurrence of "3.2.10"
Merge pull request #15 from fotioslindiakos/persistent_assets

Persistent Rails assets
Update Gemfile.lock
Merge pull request #20 from mrunalp/master

BZ 915699
Remove Gemfile.lock
Update Rails to 3.2.13.

This addresses [CVE-2013-1855] XSS vulnerability in sanitize_css in
Action Pack. See
https://groups.google.com/forum/?fromgroups=#!topic/rubyonrails-security/4_QHo4BqnN8
for the announcement.
Merge pull request #21 from BanzaiMan/master

Remove Gemfile.lock, and update to Rails 3.2.13.
Support future Rails 3.2.x and Rack 1.4.x.
Adding back Gemfile.lock, since it is required for `bundle install --deployment`

Ideally, we should be intelligent enough to detect the absence/prsence of
Gemfile.lock and modify `bundle install` command appropriately.
Until then, we keep the Gemfile.lock in the repo.
Fix the default page.
correct grammar
Merge pull request #22 from jb/patch-1

correct grammar