outsource hash function

tg_server/hash.lua

@@ -0,0 +1,7 @@
+function hash(str)
+    local hash = 0
+    for i = 1, #str do
+        hash = (hash * 31 + string.byte(str, i)) % 65536
+    end
+    return string.format("%04X", hash)
+end