Add docs for cqlengine

Author: CharAct3

README.rst

@@ -70,6 +70,79 @@ Usage
 
 Python 3.5+ is required
 
+
+Using with cqlengine
+-----
+
+.. code-block:: python
+
+    import asyncio
+    import uuid
+    import os
+
+    from aiocassandra import aiosession, AioModel
+    from cassandra.cluster import Cluster
+    from cassandra.cqlengine import columns, connection, management
+
+    cluster = Cluster()
+    session = cluster.connect()
+
+
+    class User(AioModel):
+        user_id = columns.UUID(primary_key=True)
+        username = columns.Text()
+
+
+    async def main():
+        aiosession(session)
+
+        # Set aiosession for cqlengine
+        session.set_keyspace('example_keyspace')
+        connection.set_session(session)
+
+        # Model.objects.create() and Model.create() in async way:
+        user_id = uuid.uuid4()
+        await User.objects.async_create(user_id=user_id, username='user1')
+        # also can use: await User.async_create(user_id=user_id, username='user1)
+
+        # Model.objects.all() and Model.all() in async way:
+        print(list(await User.async_all()))
+        print(list(await User.objects.filter(user_id=user_id).async_all()))
+
+        # Model.object.update() in async way:
+        await User.objects(user_id=user_id).async_update(username='updated-user1')
+
+        # Model.objects.get() and Model.get() in async way:
+        user = await User.objects.async_get(user_id=user_id)
+        assert user.user_id == (await User.async_get(user_id=user_id)).user_id
+        print(user, user.username)
+
+        # obj.save() in async way:
+        user.username = 'saved-user1'
+        await user.async_save()
+
+        # obj.delete() in async way:
+        await user.async_delete()
+
+        # Didn't break original functions
+        print('Left users: ', len(User.objects.all()))
+
+
+    def create_keyspace(keyspace):
+        os.environ['CQLENG_ALLOW_SCHEMA_MANAGEMENT'] = 'true'
+        connection.register_connection('cqlengine', session=session, default=True)
+        management.create_keyspace_simple(keyspace, replication_factor=1)
+        management.sync_table(User, keyspaces=[keyspace])
+
+
+    create_keyspace('example_keyspace')
+
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(main())
+    cluster.shutdown()
+    loop.close()
+
+
 Thanks
 ------