Support sending notifications in batch. (#27)

README.md

@@ -23,6 +23,31 @@ client.send_notification(token_hex, payload)
 
 [iOS Reference Library: Local and Push Notification Programming Guide][a1]
 
+## Contributing
+
+To develop PyAPNs2, check out the code and install dependencies. It's recommended to use a virtualenv to isolate dependencies:
+```shell
+# Clone the source code.
+git clone https://github.com/Pr0ger/PyAPNs2.git
+cd PyAPNs2
+# Create a virtualenv and install dependencies.
+virtualenv venv
+. venv/bin/activate
+pip install -e .
+```
+
+To run the tests:
+```shell
+pip install -r requirements-dev.txt
+python -m unittest discover test
+```
+
+To run the linter:
+```shell
+pip install pylint
+pylint --reports=n apns2 test
+```
+
 ## License
 
 PyAPNs2 is distributed under the terms of the MIT license.