Make resources hashable, so that they can be added to `set`s

Signed-off-by: Flavio Curella <flavio.curella@gmail.com>

docker/models/resource.py

@@ -23,6 +23,9 @@ class Model(object):
     def __eq__(self, other):
         return isinstance(other, self.__class__) and self.id == other.id
 
+    def __hash__(self):
+        return hash("%s:%s" % (self.__class__.__name__, self.id))
+
     @property
     def id(self):
         """

tests/unit/models_resources_test.py

@@ -12,3 +12,17 @@ class ModelTest(unittest.TestCase):
         container.reload()
         assert client.api.inspect_container.call_count == 2
         assert container.attrs['Name'] == "foobar"
+
+    def test_hash(self):
+        client = make_fake_client()
+        container1 = client.containers.get(FAKE_CONTAINER_ID)
+        my_set = set([container1])
+        assert len(my_set) == 1
+
+        container2 = client.containers.get(FAKE_CONTAINER_ID)
+        my_set.add(container2)
+        assert len(my_set) == 1
+
+        image1 = client.images.get(FAKE_CONTAINER_ID)
+        my_set.add(image1)
+        assert len(my_set) == 2