Sample application
Configure Apipie-rails gem

    echo "gem 'apipie-rails', '~> 0.0.18'" >> Gemfile
    bundle install
    rails g apipie:install --api_path ""

the --api_path sets api_base_url for this app (by default it's '/api')
First cut API documentation

Extracted from `routes.rb` and functional tests by running:

    APIPIE_RECORD=params rake test:functionals
    APIPIE_RECORD=examples rake test:functionals
Static html files generated

By running:

    rake apipie:static
New API version
Record examples for more versions

Run

    APIPIE_RECORD=examples rake test:functionals
Generate static html for version 2

Run

    rake apipie:static[2]
DRY params definitions
Give up keeping the git log as tutorial.

It's hard to maintain. Readme is the right place to keep it.