Add destroy method for Link

.gitignore

@@ -4,6 +4,7 @@
 .eggs/
 .vagrant/
 dist/
+.DS_Store
 
 # Tests
 .coverage

omise/__init__.py

@@ -1244,6 +1244,33 @@ def reload(self):
             self._request('get',
                           self._instance_path(self._attributes['id'])))
 
+    def destroy(self):
+        """Delete the link from the server.
+
+        Basic usage::
+
+            >>> import omise
+            >>> omise.api_secret = 'skey_test_4xsjvwfnvb2g0l81sjz'
+            >>> link = omise.Link.retrieve('link_test_5dsoxxan7gxrqihu8rs')
+            >>> link.destroy()
+            <Link id='link_test_5dsoxxan7gxrqihu8rs' at 0x7fcc349bdd90>
+            >>> link.destroyed
+            True
+
+        :rtype: Link
+        """
+        return self._reload_data(
+            self._request('delete',
+                          self._instance_path(self.id)))
+
+    @property
+    def destroyed(self):
+        """Returns ``True`` if the link has been deleted.
+
+        :rtype: bool
+        """
+        return self._attributes.get('deleted', False)
+
 
 class Occurrence(_MainResource, Base):
     """API class representing occurrence information.

omise/test/test_link.py

@@ -14,6 +14,33 @@ def _getCollectionClass(self):
         from .. import Collection
         return Collection
 
+    def _makeOne(self):
+        return self._getTargetClass().from_data({
+            'object': 'link',
+            'id': 'link_test',
+            'livemode': False,
+            'location': '/links/link_test',
+            'amount': 10000,
+            'currency': 'thb',
+            'used': False,
+            'multiple': False,
+            'description': 'Description of order-384',
+            'title': 'Order-384',
+            'charges': {
+                'object': 'list',
+                'from': '1970-01-01T07:00:00+07:00',
+                'to': '2017-03-03T19:22:33+07:00',
+                'offset': 0,
+                'limit': 20,
+                'total': 0,
+                'order': None,
+                'location': '/links/link_test/charges',
+                'data': []
+            },
+            'payment_uri': 'http://link.example.com/0BB268C6',
+            'created': '2017-03-03T12:16:48Z'
+        })
+
     @mock.patch('requests.post')
     def test_create(self, api_call):
         class_ = self._getTargetClass()
@@ -178,3 +205,24 @@ def test_retrieve_no_args(self, api_call):
         self.assertTrue(links[1].id, 'link_test_2')
         self.assertTrue(links[1].amount, 20000)
         self.assertRequest(api_call, 'https://api.omise.co/links')
+
+    @mock.patch('requests.delete')
+    def test_destroy(self, api_call):
+        link = self._makeOne()
+        class_ = self._getTargetClass()
+        self.mockResponse(api_call, """{
+            "object": "link",
+            "id": "link_test",
+            "livemode": false,
+            "deleted": true
+        }""")
+
+        self.assertTrue(isinstance(link, class_))
+        self.assertEqual(link.id, 'link_test')
+
+        link.destroy()
+        self.assertTrue(link.destroyed)
+        self.assertRequest(
+            api_call,
+            'https://api.omise.co/links/link_test'
+        )