chore(docs): add key generation step

README.md

@@ -27,9 +27,7 @@ npm run dev
 
 If you want to use your own database leave, the `DATABASE_URL` property filled in `docker/docker-compose.yml` with your databse credentials, otherwise you'll have to delete it.
 
-(wait for `start-prod` script to finish)
-
-```
+```shell
 cd docker
 make build
 make start-prod
@@ -39,10 +37,29 @@ make start-prod
 
 Env var to define :
 
-```
+```shell
 DOCKER_USERNAME="Your docker username"
 DOCKER_PASSWORD="Your docker password"
 SSH_HOST="Your SSH host"
 SSH_USERNAME="Your SSH username"
-SSH_KEY="Your SSH key"
+SSH_KEY="Your SSH key" # see below
 ```
+
+> As a good practice, SSH Key should be generated on local machine instead of target/server/remote machine
+
+Generate :
+
+```shell
+ssh-keygen -t rsa -b 4096
+# you can save the file in your current folder since you're not supposed to use it personnaly (its purpose is only to be used by CI/CD)
+```
+
+Copy :
+
+```shell
+cat ~/.ssh/id_rsa.pub | ssh b@B 'cat >> ~/.ssh/authorized_keys'
+# or
+ssh-copy-id -i ~/.ssh/id_rsa.pub user@host
+```
+
+> Source: https://github.com/appleboy/ssh-action#setting-up-a-ssh-key