Update README.md on docker selfhost commands (#42)

* update README docker commands

* update README.md and docker-compose.yml reg user permissions.

* Note on deno user id

* add comment to `mkdir` and EOF diff fix

docker-compose.yml

@@ -5,7 +5,6 @@ services:
     ports:
       - 127.0.0.1:8000:8000
     mem_limit: '256m'
-    user: '${UID}:${GID}' # if you run into issues with permissions for the data-files volume below, see other options at https://stackoverflow.com/a/56904335
     env_file:
       - path: .env
         required: true