Schema builder helpers

[rmasters]

A nice-to-have if it's possible to add these - emulate the timestamps() helper for schema building:

Schema::create('comments', function($table) {
    $table->increments('id');

    $table->createdBy();
    $table->updatedBy();
    $table->deletedBy();
});

Aliasing to something like:

$table->integer('created_by_id')->unsigned();
$table->foreign('created_by_id')->references('id')->on(Config::get('culpa::users.table'));