Add --with-redis flag to list of available build flags in README.
diff --git a/README.md b/README.md
index dae6a76..b6779bd 100644
--- a/README.md
+++ b/README.md
@@ -88,6 +88,9 @@ The waf build system for libgit2 accepts the following flags:
--with-sqlite
Enable sqlite support.
+ --with-redis
+ Enable redis support.
+
You can run `./waf --help` to see a full list of install options and
targets.