chore(tooling): improve README and Makefile

GNUmakefile

@@ -37,8 +37,8 @@ push: tidy no-dirty check ## push changes to git remote
 
 .PHONY: deploy
 deploy: build ## deploy changes to the production server
-	rsync ./ods root@ods.adyxax.org:/usr/local/bin/
-	ssh root@ods.adyxax.org "systemctl restart ods"
+	rsync ./ods ods@ods.adyxax.org:
+	ssh ods@ods.adyxax.org "systemctl --user restart ods"
 
 ##### Utils ####################################################################
 .PHONY: confirm

README.md

@@ -16,6 +16,13 @@ help` if running BSD) to see the possible actions.
 
 Use `make build` to build a static binary of the service, embedding everything.
 
+## Configuration
+
+ODS can be configured by setting the following environment variables:
+- `ODS_DEBUG`: Set this to a non empty string to activate debug logs.
+- `ODS_HOST`: Hostname or address to listen on, defaults to `127.0.0.1`.
+- `ODS_PORT`: TCP port to listen on, defaults to `8080`.
+
 ## The dictionary
 
 The "Officiel Du Scrabble" (ODS for short) is what the official dictionary for