added link to ssb-server

Author: retog

README.md

@@ -25,7 +25,7 @@ Building
 
 Running
 
-To use Scuttle Shell Browser you need an ssb-sever running on your machine (this is the case when you
+To use Scuttle Shell Browser you need an [ssb-server](https://github.com/ssbc/ssb-server) running on your machine (this is the case when you
 are running Patchwork). You need to install native messaging for the manifest in `host/scuttle_shell_browser.json`, see https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Native_messaging to learn how to do this on your platform. Note that you need to adapt the paths in the manifest file and that `host/host-script.js` must be executable.