How do I get python to store data from multiple people?

I'm trying to make a discord.py async bot that rewards people with brownie points when asked (hehe). It's supposed to be a local bot for me and my friends, but I don't want to update everyone's brownie point into the code every time I restart it. my code is here:

import command

import discord
from discord.ext.commands import Bot
from discord.ext import commands
import asyncio
import time
import random

#Here is the basic command:
#await client.send_message(message.channel, messsage)

#global hub
me = 0
discordname = "PRIVATE"

Client = discord.Client()
client = commands.Bot(command_prefix = "")

@client.event
async def on_ready():
    print ("the brownies are loaded and ready to go!")

@client.event
async def on_message(message):
    if message.content.startswith("bb! give"):
        args = message.content.split(" ")
        if args[1:][1] == "(my user ID)":
            global me
            global discordname
            me = me + int(args[1:][2])
            await client.send_message(message.channel, str(int(args[1:][2])) + "  brownie points have been given to " + str(discordname))
    if message.content.startswith("bb! brownies"):
        args = message.content.split(" ")
        if args[1:][1] == "(my user ID)":
            await client.send_message(message.channel, str(discordname) + " 
currently has " + str(me) + " brownie points.")

client.run(TOKEN)

I want the bot to create a new variable every time a user joins the server. However, every attempt I've tried (ie pickle module, shelve module...) has produced one of the following consequences:

1. it does nothing
2. it fails
3. it returns an error