feat(ruby): introduced new ruby-version JSON parameter.

This removes a misleading `ruby-ng.ruby_version` paramater in favor of
new universal `ruby-version`. The problem was, that the old one was used
for both distributions (Ubuntu and Amazon Linux) while in fact,
`ruby-ng` was referring to Ubuntu-only cookbook.

The new parameter is distro-agnostic and cookbook-agnostic, clearly
speaking it's intention.

Resolves #156

BREAKING CHANGE: If you were using `ruby-ng.ruby_version` JSON
configuration parameter in your stack/layer configuration, please change
it to `ruby-version`. Since `ruby-version` is set by default to the
freshest version of ruby available, you may end up with unexpected
upgrade of ruby on your system.

.kitchen.yml

@@ -193,5 +193,4 @@ suites:
           webserver:
             adapter: 'apache2'
             port: 8081
-      'ruby-ng':
-        ruby_version: '2.3'
+      'ruby-version': '2.3'

attributes/default.rb

@@ -7,7 +7,7 @@
 
 # ruby
 default['build-essential']['compile_time'] = true
-default['ruby-ng']['ruby_version'] = node['ruby'].try(:[], 'version') || '2.5'
+default['ruby-version'] = node['ruby'].try(:[], 'version') || '2.5'
 default['nginx']['source']['modules'] = %w[
   nginx::http_ssl_module nginx::http_realip_module nginx::http_gzip_static_module nginx::headers_more_module
   nginx::http_stub_status_module

docs/source/attributes.rst

@@ -34,12 +34,17 @@ convention).
      of an application, not included in this list - it will be skipped, as this list
      takes precedence over anything else.
 
--  ``node['ruby-ng']['ruby_version']``
+-  ``node['ruby-version']``
 
   -  **Type:** string
   -  **Default:** ``2.5``
-  -  Sets the Ruby version used through the system. See `ruby-ng cookbook documentation`_
-     for more details
+  -  Sets the Ruby version used through the system. For debian-based distributions,
+     a ``ruby-ng`` cookbook is used (check `ruby-ng cookbook documentation`_).
+     For Amazon Linux, packages provided by distribution (i.e. ``ruby23``,
+     ``ruby23-devel`` etc.).
+     **Important** please note, that some versions may be available on one system,
+     and not on the other (for example ``ruby-ng`` gets freshest versions of ruby
+     way earlier than Amazon Linux).
 
 Cross-application attributes
 ----------------------------

recipes/setup.rb

@@ -44,9 +44,10 @@
 
 # Ruby and bundler
 if node['platform_family'] == 'debian'
+  node.default['ruby-ng']['ruby_version'] = node['ruby-version']
   include_recipe 'ruby-ng::dev'
 else
-  ruby_pkg_version = node['ruby-ng']['ruby_version'].split('.')[0..1]
+  ruby_pkg_version = node['ruby-version'].split('.')[0..1]
   package "ruby#{ruby_pkg_version.join('')}"
   package "ruby#{ruby_pkg_version.join('')}-devel"
   execute "/usr/sbin/alternatives --set ruby /usr/bin/ruby#{ruby_pkg_version.join('.')}"