📝 Update doc

Author: JulianKropp

hedgedoc/README.md

@@ -15,6 +15,7 @@ MYSQL_ROOT_PASSWORD='XXXXXXXXXXXXXXXXXXXXXXXX'
 MYSQL_DATABASE=hedgedoc
 MYSQL_USER=hedgedoc
 MYSQL_PASSWORD='XXXXXXXXXXXXXXXXXXXXXXXX'
+#CMD_OAUTH2_CLIENT_SECRET='XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' # Advanced (Add Authelia as OIDC)
 ```
 ## Start
 ```sh
@@ -35,7 +36,7 @@ To login through Authelia you have to add the following lines to the environment
     environment:
       #Authelia as OIDC
       - CMD_OAUTH2_CLIENT_ID=hedgedoc
-      - CMD_OAUTH2_CLIENT_SECRET=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+      - CMD_OAUTH2_CLIENT_SECRET=${CMD_OAUTH2_CLIENT_SECRET}
       - CMD_OAUTH2_AUTHORIZATION_URL=https://auth.${DOMAIN}/api/oidc/authorization
       - CMD_OAUTH2_TOKEN_URL=https://auth.${DOMAIN}/api/oidc/token
       - CMD_OAUTH2_USER_PROFILE_URL=https://auth.${DOMAIN}/api/oidc/userinfo