Update docs.

laravel/documentation/database/eloquent.md

@@ -36,12 +36,14 @@ ## Conventions
 - Each table should have a primary key named **id**.
 - Each table name should be the plural form of its corresponding model name.
 
-Sometimes you may wish to use a table name other than the plural form of your model. No problem. Just add a static **table** property your model:
+Sometimes you may wish to use a table name other than the plural form of your model, or a diffrent primary key column. No problem. Just add a static **table** property your model:
 
 	class User extends Eloquent {
 
 	     public static $table = 'my_users';
 
+	     public static $key = 'my_primary_key';
+
 	}
 
 <a name="get"></a>