Update the install documentation to user manage.py

INSTALL.md

@@ -183,30 +183,24 @@ Then create two files in this directory:
  - ``cert.pem`` contains the certificate,
  - ``key.pem`` contains the key pair.
 
-Bootstrapping the database
-==========================
+Creating the first admin user
+=============================
 
-Freeposte.io does not yet have a database initialization or migration system.
-This will be added in version ``1.1``. For now, you will have to manually
-bootstrap the database. First, start the mail server stack:
+Freeposte.io does not come with any default user. You have to create the
+first admin user manually. First, start the mail server stack:
 
 ```
 docker-compose up -d
 ```
 
-Then bootstrap the database:
+Then create the admin user:
 
 ```
-docker exec -i -t freeposte_admin_1 python initdb.py
-docker-compose restart
+docker exec -i -t freeposte_admin_1 python manage.py admin admin exmaple.net admin
 ```
 
-Be very careful and run this command only once, as it will remove any existing
-data before creating a fresh database.
-
-The default user is ``admin@example.com`` with password ``admin``. Connect to
-the Web admin interface and setup a proper domain with your own admin user
-before removing the default one:
+This will create ``admin@example.net`` with password ``admin``. Connect to
+the Web admin interface change the password to a strong one:
 
 ```
 https://your-host-name.tld/admin/