Add missing option from geoip backend

diff --git a/docs/markdown/authoritative/backend-geoip.md b/docs/markdown/authoritative/backend-geoip.md
index bae6d41554b9d5f700a43b1cf8cff82b2680d871..f65fdaf6d72bcfe5d55989de8410af92be05b113 100644 (file)
--- a/docs/markdown/authoritative/backend-geoip.md
+++ b/docs/markdown/authoritative/backend-geoip.md
@@ -27,6 +27,11 @@ Specifies the full path of the data file for IPv4 to use.
 ### `geoip-database-file6`
 Specifies the full path of the data file for IPv6 to use.
 
+### `geoip-database-cache`
+Specifies the kind of caching that is done on the database. This is one of
+"standard", "memory", "index" or "mmap". These options map to the caching
+options described [here](https://github.com/maxmind/geoip-api-c/blob/master/README.md#memory-caching-and-other-options)
+
 ### `geoip-zones-file`
 Specifies the full path of the zone configuration file to use.