Added URLField and SlugField.

Fixed test_modelserializer_max_length_exceeded

rest_framework/fields.py

@@ -700,6 +700,23 @@ class CharField(WritableField):
         return smart_unicode(value)
 
 
+class URLField(CharField):
+    type_name = 'URLField'
+
+    def __init__(self, **kwargs):
+        kwargs['max_length'] = kwargs.get('max_length', 200)
+        kwargs['validators'] = [validators.URLValidator()]
+        super(URLField, self).__init__(**kwargs)
+
+
+class SlugField(CharField):
+    type_name = 'SlugField'
+
+    def __init__(self, *args, **kwargs):
+        kwargs['max_length'] = kwargs.get('max_length', 50)
+        super(SlugField, self).__init__(*args, **kwargs)
+
+
 class ChoiceField(WritableField):
     type_name = 'ChoiceField'
     widget = widgets.Select

rest_framework/serializers.py

@@ -441,6 +441,8 @@ class ModelSerializer(Serializer):
             models.DateField: DateField,
             models.EmailField: EmailField,
             models.CharField: CharField,
+            models.URLField: URLField,
+            models.SlugField: SlugField,
             models.TextField: CharField,
             models.CommaSeparatedIntegerField: CharField,
             models.BooleanField: BooleanField,

rest_framework/tests/serializer.py

@@ -245,7 +245,7 @@ class ValidationTests(TestCase):
         }
         serializer = ActionItemSerializer(data=data)
         self.assertEquals(serializer.is_valid(), False)
-        self.assertEquals(serializer.errors, {'content': [u'Ensure this value has at most 200 characters (it has 201).']})
+        self.assertEquals(serializer.errors, {'title': [u'Ensure this value has at most 200 characters (it has 201).']})
 
 
 class MetadataTests(TestCase):