Update 'Home'

Home.md

@@ -10,6 +10,28 @@ You can't, not with this particular setup. I wanted to support both sharing a si
 
 Location is entirely cosmetic so I've decided that adding complexity to optionally strip it wasn't worth it. If you disagree and can't stand ``/tt-rss/`` in the URL, you'll have to modify things a bit to get rid of it.
 
+### How do I set global configuration options?
+
+Through the environment. For example, to set `SELF_URL_PATH`, add the following to `.env`:
+
+```ini
+TTRSS_SELF_URL_PATH=http://example.com/tt-rss
+```
+
+Note that to set a boolean option to `false` you should use empty string as value, not string literal "false", like so:
+
+```ini
+TTRSS_SINGLE_USER_MODE=
+```
+
+This, however, would actually **enable** it:
+
+```ini
+TTRSS_SINGLE_USER_MODE=false
+```
+
+Don't use quotes around values.
+
 ### How do I customize the YML without commiting my changes to git?
 
 You can use [docker-compose.override.yml](https://docs.docker.com/compose/extends/). For example, customize `db` to use a different postgres image: