Just fixing a small typo.

README.md

@@ -364,7 +364,7 @@ Also, stick with the following rules:
 
 * There is no need to +alias_method_chain+ your initialize method in models that don't use `default_value_for`.
 
-* Make sure that +alias_method_chain+ is called *after* the last `default_value_for` occurance.
+* Make sure that +alias_method_chain+ is called *after* the last `default_value_for` occurrence.
 
 If your default value is accidentally similar to default_value_for's options hash wrap your default value like this:
 
@@ -553,4 +553,4 @@ I've wanted such functionality for a while now and it baffled me that ActiveReco
 
 Thanks to Pratik Naik for providing the initial code snippet on which this plugin is based on: http://m.onkey.org/2007/7/24/how-to-set-default-values-in-your-model
 
-Thanks to Norman Clarke and Tom Mango for Rails 4 support.
+Thanks to Norman Clarke and Tom Mango for Rails 4 support.