Notes on refreshing cache, mentioned ffaddon interwiki link

README.md

@@ -4,6 +4,8 @@ A collection of tweaks I've made to my personal wiki. Currently extra interwiki
 ## Installation
 Add contents to your wiki's base directory.
 
+When added new interwiki icons you need to clear-out the wiki's cache with `rm -rf data/cache/*/*.{gif,png,css}`
+
 ## Contents
 
 ### Interwiki Links
@@ -19,6 +21,7 @@ Icons and definitions for:
 - Blueberry Soft
 - Chocolatey packages
 - Duck Duck Go search
+- Firefox Add-ons
 - Github
 - Game Making Tools Wiki
 - IMDB film pages