fix: handle optional leading "@" in script_path()

Closes #71

webui.lua

@@ -8,8 +8,15 @@ local url = require("socket.url")
 local MSG_PREFIX = "[webui] "
 local VERSION = "2.0.0"
 
+function string.starts(String, Start)
+  return string.sub(String,1,string.len(Start))==Start
+end
+
 local function script_path()
-  local str = debug.getinfo(2, "S").source:sub(2)
+  local str = debug.getinfo(2, "S").source
+  if string.starts(str,"@") then
+    str = str:sub(2)
+  end
   return str:match("(.*/)")
 end
 
@@ -431,10 +438,6 @@ local function header(code, content_type, content_length)
   end
 end
 
-function string.starts(String, Start)
-  return string.sub(String,1,string.len(Start))==Start
-end
-
 local function concatkeys(tab, sep)
   local inter = {}
   for key,_ in pairs(tab) do