The only rule here is that there must be at least one. A realm consists of a
name, which is used to reference the realm, a credential and a store.
-You can also specify as realm class to instantiate instead of the default
-L<Catalyst::Authentication::Realm> class.
+You can also specify a realm class to instantiate instead of the default
+L<Catalyst::Authentication::Realm> class using the 'class' element within the
+realm config.
Each realm config contains two hashes, one called 'credential' and one called
'store', each of which provide configuration details to the respective modules.