add example of how to use the new config feature

eatit-cfg.lua

@@ -21,6 +21,9 @@ plugins = { -- the  plugins you want to load
   { 'https://git.squi.bid/eat-it',
     file = 'eatit.lua',
     dir = 'scripts',
+    cfg = function()
+      print('this is an example')
+    end
   },
 }