chore(cache): clear the cache before filling it

Closes https://github.com/FXServer-ESX/fxserver-esx_whitelist/issues/2

server/main.lua

@@ -5,6 +5,8 @@ function loadWhiteList ()
     'SELECT * FROM whitelist',
     {},
     function (identifiers)
+      Whitelist = {}
+
       for i=1, #identifiers, 1 do
         table.insert(WhiteList, tostring(identifiers[i].identifier))
       end