Auto create config file if it doesn't exist

flairtimercomment.py

@@ -11,11 +11,12 @@ if not os.path.exists(default_config_path):
     os.makedirs('config', exist_ok=True)
     with open(default_config_path, 'w') as f:
         f.write(
+            '# Reddit API credentials\n'
             'username = ""\n'
             'password = ""\n'
             'client_id = ""\n'
             'client_secret = ""\n'
-            'user_agent = "Flair Timer Comment Bot"\n'
+            'user_agent = "Flair Timer Comment Bot" # Must be unique and descriptive\n'
             '\n'
             '# Subreddits\n'
             'subreddit = ""\n'