Docs updates

docs/installation-guide.rst

@@ -73,6 +73,7 @@ Configure systemd
     GENIEACS_FS_ACCESS_LOG_FILE=/var/log/genieacs/genieacs-fs-access.log
     GENIEACS_UI_ACCESS_LOG_FILE=/var/log/genieacs/genieacs-ui-access.log
     GENIEACS_DEBUG_FILE=/var/log/genieacs/genieacs-debug.yaml
+    GENIEACS_EXT_DIR=/opt/genieacs/ext
     GENIEACS_UI_JWT_SECRET=secret
   
   Set file ownership and permissions:
@@ -82,7 +83,7 @@ Configure systemd
     sudo chown genieacs:genieacs /opt/genieacs/genieacs.env
     sudo chmod 600 /opt/genieacs/genieacs.env
 
-.. topic:: Create logs directory  
+.. topic:: Create logs directory
 
   .. code:: bash