Create Sluggable concern, generates slug using name attribute before validation

Why:

* We need a way to generate a slug for a object given his name attribute value

How:

* A concern that generates the slug before validation

app/models/concerns/sluggable.rb

@@ -0,0 +1,11 @@
+module Sluggable
+  extend ActiveSupport::Concern
+
+  included do
+    before_validation :generate_slug
+  end
+
+  def generate_slug
+    self.slug = name.to_s.parameterize
+  end
+end