Access control documentation: Flush caches capability

Describes the capability that grants rights to operate the
'flush-caches' ssh command.

Change-Id: Iedbfca1dd43eb6aaf6994149868b01ad2453aa31
Signed-off-by: Fredrik Luthander <fredrik.luthander@sonymobile.com>
diff --git a/Documentation/access-control.txt b/Documentation/access-control.txt
index 2db6a19..b1f01fd 100644
--- a/Documentation/access-control.txt
+++ b/Documentation/access-control.txt
@@ -833,8 +833,6 @@
 Below you find a list of capabilities available:
 
 
-* Flush Caches
-
 * Kill Task
 
 * Priority
@@ -887,6 +885,18 @@
 or via the web UI.
 
 
+[[capability_flushCaches]]
+Flush Caches
+~~~~~~~~~~~~
+
+Allow the flushing of Gerrits caches.  This capability allows the granted
+group to link:cmd-flush-caches.html[flush some or all Gerrit caches via ssh].
+
+[NOTE]
+This capability doesn't imply permissions to the show-caches command.  For that
+you need the <<capability_viewCaches,view caches capability>>.
+
+
 [[capability_queryLimit]]
 Query Limit
 ~~~~~~~~~~~
diff --git a/Documentation/cmd-flush-caches.txt b/Documentation/cmd-flush-caches.txt
index f8882c8..bc6fac5 100644
--- a/Documentation/cmd-flush-caches.txt
+++ b/Documentation/cmd-flush-caches.txt
@@ -26,7 +26,8 @@
 ACCESS
 ------
 Caller must be a member of the privileged 'Administrators' group,
-or have granted the 'Flush Caches' global capability.
+or in a group that have been granted
+link:access-control.html#capability_flushCaches[the 'Flush Caches' global capability].
 
 SCRIPTING
 ---------