As discussed..

modules/ruby/manifests/init.pp

Index: modules/ruby/manifests/init.pp
diff --git a/modules/ruby/manifests/init.pp b/modules/ruby/manifests/init.pp
new file mode 100644
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+++ b/modules/ruby/manifests/init.pp
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+# == 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 clone and build.
+#
+# === Examples:
+#
+#   class {'ruby':
+#     version => '2.2.0',
+#   }
+#
+class ruby(
+  $version = '2.1.5',
+) {
+
+  $ruby_install_source_url = 'https://github.com/postmodern/ruby-install.git'
+  $ruby_install_source_dir = "/root/ruby-install"
+
+  Package {
+    ensure => 'installed',
+  }
+
+  Exec {
+    logoutput => true,
+    path => '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin',
+  }
+
+  if !defined(Package['git']) {
+    package {'git': }
+  }
+
+  exec {'ruby-clone-ruby-install':
+    command => shellquote('git', 'clone', $ruby_install_source_url, $ruby_install_source_dir),
+    creates => $ruby_install_source_dir,
+  }
+  ->
+  exec {'ruby-execute-ruby-install':
+    command => shellquote("$ruby_install_source_dir/bin/ruby-install", '--system', 'ruby', $ruby_version),
+    creates => "/usr/local/bin/ruby",
+  }
+
+  Exec['ruby-clone-ruby-install'] <- Package['git']
+}