Added small bit of info about upgrading

templates/Snipe-IT/0/README.md

@@ -4,4 +4,8 @@
 ### Generate Your App Key Using:
 `php artisan key:generate`
 
-https://snipe-it.readme.io/docs/generate-your-app-key
+https://snipe-it.readme.io/docs/generate-your-app-key
+
+
+### After upgrading to a later version, use:
+`php artisan migrate`