As discussed..

modules/ruby/manifests/init.pp

+# == Class: ruby
+#
+# Perform a custom Ruby installation based on the ruby-install script,
+# using /usr/local as installation prefix.
+#
+# === Parameters:
+#
+# [*version*]
+#   The Ruby version to build and install.
+#
+# === Examples:
+#
+#   class {'ruby':
+#     version => '2.2.0',
+#   }
+#
+class ruby(
+  $version = '2.1.5',
+) {
+
+  $install_src_url = 'https://github.com/postmodern/ruby-install.git'
+  $install_src_dir = '/root/ruby-install'
+  $install_command = "$install_src_dir/bin/ruby-install"
+
+  Exec {
+    logoutput => true,
+    path => '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin',
+  }
+
+  if !defined(Package['git']) {
+
+    package {'git':
+      ensure => 'installed',
+    }
+  }
+
+  exec {'ruby-clone-ruby-install':
+    command => shellquote('git', 'clone', $install_src_url, $install_src_dir),
+    creates => $install_src_dir,
+    require => Package['git'],
+  }
+  ->
+  exec {'ruby-execute-ruby-install':
+    command => shellquote($install_command, '--system', 'ruby', $version),
+    creates => '/usr/local/bin/ruby',
+  }
+}