haven't -> have not

Author: Archmonger

docs/src/installation/index.md

@@ -29,7 +29,7 @@ In your settings you will need to add `django_idom` to [`INSTALLED_APPS`](https:
 
     Django-IDOM requires ASGI in order to use Websockets.
 
-    If you haven't enabled ASGI on your **Django project** yet, you will need to install `channels[daphne]`, add `daphne` to `INSTALLED_APPS`, then set your `ASGI_APPLICATION` variable.
+    If you have not enabled ASGI on your **Django project** yet, you will need to install `channels[daphne]`, add `daphne` to `INSTALLED_APPS`, then set your `ASGI_APPLICATION` variable.
 
     Read the [Django Channels Docs](https://channels.readthedocs.io/en/stable/installation.html) for more info.