Fix typo in the gem's name.

README.md

@@ -1,6 +1,6 @@
 # PublicActivity [![Build Status](https://secure.travis-ci.org/pokonski/public_activity.png)](http://travis-ci.org/pokonski/public_activity) [![Dependency Status](https://gemnasium.com/pokonski/public_activity.png)](https://gemnasium.com/pokonski/public_activity) [![Code Climate](https://codeclimate.com/github/pokonski/public_activity.png)](https://codeclimate.com/github/pokonski/public_activity) [![Gem Version](https://badge.fury.io/rb/public_activity.png)](http://badge.fury.io/rb/public_activity)
 
-_public_activity_ provides easy activity tracking for your **ActiveRecord**, **Mongoid 3** and **MongoMapper** models
+`public_activity` provides easy activity tracking for your **ActiveRecord**, **Mongoid 3** and **MongoMapper** models
 in Rails 3. Simply put: it records what has been changed or created and gives you the ability to present those
 recorded activities to users - in a similar way to how GitHub does it.