api: makes sure field type is always part of the schema

tests/test_api.py

@@ -142,6 +142,7 @@ def test_formdef_schema():
     resp = get_app(pub).get('/test/schema')
     assert resp.json['name'] == 'test'
     assert resp.json['fields'][0]['label'] == 'foobar'
+    assert resp.json['fields'][0]['type'] == 'string'
 
 def test_categories():
     Category.wipe()

wcs/fields.py

@@ -150,6 +150,8 @@ class Field(object):
             if hasattr(self, attribute) and getattr(self, attribute) is not None:
                 val = getattr(self, attribute)
                 field[attribute] = val
+        if not 'type' in field:
+            field['type'] = self.key
         return field
 
     def init_with_json(self, elem, include_id=False):