[doc] add upgrade instructions

docs/install/debian.md

@@ -22,7 +22,7 @@ apt-get update && apt-get install yarn
 yarn add gancio --prod
 ```
 
-1. Setup with postgreSQL (optional as you can choose sqlite)
+1. Setup with postgreSQL __(optional as you can choose sqlite)__
 ```bash
 apt-get install postgresql
 # Create the database
@@ -57,6 +57,12 @@ gancio start --config config.json
 sudo yarn global add pm2
 pm2 start gancio -- --config config.json
 
-# Run this command to run your application as a service:
-sudo env PATH=$PATH:/usr/local/bin pm2 startup -u gancio
+# Run this command to run your application as a service and automatically restart after a reboot:
+pm2 startup # read the output!
+sudo pm2 startup -u gancio
 ```
+
+1. Upgrade
+
+sudo yarn global add gancio
+sudo service pm2 restart

docs/install/docker.md

@@ -82,3 +82,11 @@ docker-compose logs
 1. Point your web browser to [http://localhost:13120](http://localhost:13120) or where you specified during setup and enjoy :tada:
 
 1. You can edit `config.json` file and restart the container on your needs, see [Configuration](/config) for more details.
+
+
+## Upgrade
+
+```bash
+cd /opt/gancio
+docker-compose up -d --no-deps --build
+```