Document nested models

README.md

@@ -63,13 +63,37 @@ This will mark the `:log_entry` parameters hash and any subhash of it permitted.
 You can also use permit on nested parameters, like:
 
 ``` ruby
-params.permit(:name, {:emails => []}, :friends => [ :name, { :family => [ :name ], :hobbies => [] }])
+params.permit(
+  :name,
+  {:emails => []},
+  :friends => [ :name, { :family => [ :name ], :hobbies => [] }]
+)
 ```
 
 This declaration whitelists the `name`, `emails` and `friends` attributes. It is expected that `emails` will be an array of permitted scalar values and that `friends` will be an array of resources with specific attributes : they should have a `name` attribute (any permitted scalar values allowed), a `hobbies` attribute as an array of permitted scalar values, and a `family` attribute which is restricted to having a `name` (any permitted scalar values allowed, too).
 
 Thanks to Nick Kallen for the permit idea!
 
+## Nested models
+
+Permitting nested model attributes works like nested parameters, but you permit the key names, not the nested model names.
+
+``` ruby
+class Company
+  validates :name, presence: true
+  accepts_nested_attributes_for :people
+end
+```
+
+In the controller:
+
+``` ruby
+params.require(:company).permit(
+  :name,
+  {:people_attributes => []}
+)
+```
+
 ## Require Multiple Parameters
 
 If you want to make sure that multiple keys are present in a params hash, you can call the method twice: