Update README.md

Author: treeben77

README.md

@@ -1,2 +1,42 @@
 # DiscordOAuth2.py
 Use Discord's OAuth2 effortlessly! Turns the auth code to a access token and the access token into scope infomation.
+
+### Using DiscordOAut2.py with Flask
+
+```python
+from flask import Flask, redirect, request
+from threading import Thread
+import discordoauth2 as oauth2
+import os
+
+app = Flask('')
+oauth2.client({
+  'client_id': '849<example>993044', #the client id for your application
+  'client_secret': os.environ['oauth2_secret'], #the client secret for your application. Be super-extra-very-we-are-not-kidding-like-really-be-secure-make-sure-your-info-is-not-in-your-source-code careful with this.
+  'redirect_uri': 'https://example.com/oauth2', #the redirect for the uri below
+  'bot_token': os.environ['bot_token'] #the token for your app's bot, only required if you need to use guild.join
+})
+
+oauth2_uri = "https://discord.com/api/oauth2/authorize?client_id=849<example>993044&redirect_uri=https%3A%2F%2Fexample.com%2Foauth2&response_type=code&scope=identify"
+
+@app.route('/oauth2')
+def oauth():
+  code = request.args.get('code')
+  if not code:
+    return redirect(oauth2_uri)
+  else:
+    token = oauth2.exchange_code(code)
+    if str(token) == """{'error': 'invalid_request', 'error_description': 'Invalid "code" in request.'}""":
+      return redirect(oauth2_uri)
+    identify = oauth2.get_identify(token['access_token'])
+    connections = oauth2.get_connections(token['access_token'])
+    guilds = oauth2.get_guilds(token['access_token'])
+    oauth2.join_guild(token['access_token'], 849912914450448395)
+    return f'{identify}<br/><br/>{connections}<br/><br/>{guilds}'
+
+def run():
+  app.run(host="0.0.0.0", port=8080)
+
+server = Thread(target=run)
+server.start()
+```