Merge pull request #48 from PaulMakepeace/add-user-os-x

Use OS X's directory service tools to manage adding user to rvm group

manifests/system_user.pp

@@ -4,9 +4,17 @@
   ensure_resource('user', $name, {'ensure' => 'present' })
   include rvm::group
 
+  $add_to_group = $osfamily ? {
+    'Darwin' => "/usr/sbin/dseditgroup -o edit -a ${name} -t user ${rvm::params::group}",
+    default  => "/usr/sbin/usermod -a -G ${rvm::params::group} ${name}",
+  }
+  $check_in_group = $osfamily ? {
+    'Darwin' => "/usr/bin/dsmemberutil checkmembership -U ${name} -G ${rvm::params::group} | grep -q 'user is a member'",
+    default  => "/bin/cat /etc/group | grep '^${rvm::params::group}:' | grep -qw ${name}",
+  }
   exec { "rvm-system-user-${name}":
-    command => "/usr/sbin/usermod -a -G ${rvm::params::group} ${name}",
-    unless  => "/bin/cat /etc/group | grep ${rvm::params::group} | grep ${name}",
+    command => $add_to_group,
+    unless  => $check_in_group,
     require => [User[$name], Group[$rvm::params::group]];
   }
 }