add refresh_user tool

admin-guide/configuration/basic/ad_integration.md

@@ -19,6 +19,15 @@ which will reload the information in the cache after 12 hours, one hour before e
 ```
 sss_cache -E
 ```
+Alternatively as normal user you may just reset the information about yourself:
+```
+refresh_user
+```
+or for someone else:
+```
+refresh_user muster_t
+```
+
 
 On nodes where looking up members of a group is not necessary (`getent group $GROUP`), you may do
 ```