Merge pull request #48 from Virusmater/patch-1

change small type for function and import os

docs/introduction.rst

@@ -47,6 +47,7 @@ in exchange for fetching user's details and display them on web page.
 
 
 .. code-block:: python3
+    import os
 
     from flask import Flask, redirect, url_for
     from flask_discord import DiscordOAuth2Session, requires_authorization, Unauthorized