add \0 in dumper would be better

Author: cloudwu

lualib/skynet/datasheet/builder.lua

@@ -12,7 +12,7 @@ local address
 local unique_id = 0
 local function unique_string(str)
 	unique_id = unique_id + 1
-	return str .. ("\0" .. tostring(unique_id))
+	return str .. tostring(unique_id)
 end
 
 local function monitor(pointer)

lualib/skynet/datasheet/dump.lua

@@ -124,7 +124,8 @@ function ctd.dump(root)
 		string.pack("<I4", doc.table_n),
 		table.concat(index),
 		table.concat(doc.table),
-		table.concat(doc.strings, "\0")
+		table.concat(doc.strings, "\0"),
+		"\0",
 	}
 	return table.concat(tmp)
 end