Better docs related to lookup_field and hyperlinked serializers. Closes #920.

Author: tomchristie

docs/api-guide/generic-views.md

@@ -60,7 +60,7 @@ The following attributes control the basic view behavior.
 
 * `queryset` - The queryset that should be used for returning objects from this view.  Typically, you must either set this attribute, or override the `get_queryset()` method.
 * `serializer_class` - The serializer class that should be used for validating and deserializing input, and for serializing output.  Typically, you must either set this attribute, or override the `get_serializer_class()` method.
-* `lookup_field` - The field that should be used to lookup individual model instances.  Defaults to `'pk'`.  The URL conf should include a keyword argument corresponding to this value.  More complex lookup styles can be supported by overriding the `get_object()` method.
+* `lookup_field` - The field that should be used to lookup individual model instances.  Defaults to `'pk'`.  The URL conf should include a keyword argument corresponding to this value.  More complex lookup styles can be supported by overriding the `get_object()` method.  Note that when using hyperlinked APIs you'll need to ensure that *both* the API views *and* the serializer classes use lookup fields that correctly correspond with the URL conf.
 
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docs/api-guide/serializers.md

@@ -387,14 +387,16 @@ There needs to be a way of determining which views should be used for hyperlinki
 
 By default hyperlinks are expected to correspond to a view name that matches the style `'{model_name}-detail'`, and looks up the instance by a `pk` keyword argument.
 
-You can change the field that is used for object lookups by setting the `lookup_field` option.  The value of this option should correspond both with a kwarg in the URL conf, and with an field on the model.  For example:
+You can change the field that is used for object lookups by setting the `lookup_field` option.  The value of this option should correspond both with a kwarg in the URL conf, and with a field on the model.  For example:
 
     class AccountSerializer(serializers.HyperlinkedModelSerializer):
         class Meta:
             model = Account
             fields = ('url', 'account_name', 'users', 'created')
             lookup_field = 'slug'
 
+Not that the `lookup_field` will be used as the default on *all* hyperlinked fields, including both the URL identity, and any hyperlinked relationships.
+
 For more specfic requirements such as specifying a different lookup for each field, you'll want to set the fields on the serializer explicitly.  For example:
 
     class AccountSerializer(serializers.HyperlinkedModelSerializer):