Fix getting started commands out of order (#1737)

In current order, docker-compose build results in
ERROR: Couldn't find env file: /a/hopt/mastodon/.env.production

README.md

@@ -72,10 +72,6 @@ The project now includes a `Dockerfile` and a `docker-compose.yml` file (which r
 Review the settings in `docker-compose.yml`. Note that it is not default to store the postgresql database and redis databases in a persistent storage location,
 so you may need or want to adjust the settings there.
 
-Before running the first time, you need to build the images:
-
-    docker-compose build
-
 Then, you need to fill in the `.env.production` file:
 
     cp .env.production.sample .env.production
@@ -85,6 +81,11 @@ Do NOT change the `REDIS_*` or `DB_*` settings when running with the default doc
 
 You will need to fill in, at least: `LOCAL_DOMAIN`, `LOCAL_HTTPS`, `PAPERCLIP_SECRET`, `SECRET_KEY_BASE`, `OTP_SECRET`, and the `SMTP_*` settings.  To generate the `PAPERCLIP_SECRET`, `SECRET_KEY_BASE`, and `OTP_SECRET`, you may use:
 
+Before running the first time, you need to build the images:
+
+    docker-compose build
+
+
     docker-compose run --rm web rake secret
 
 Do this once for each of those keys, and copy the result into the `.env.production` file in the appropriate field.