feat(/admin): add /admin command for admin management

- Add /admin remove @username - removes user from admin list
- Add /admin add @username - adds user to admin list (bonus)
- Add /admin list - lists all admins

Resolves #52

apps/telegram-bot/bot.py

@@ -8,6 +8,7 @@ from telegram.ext import Application, CommandHandler, MessageHandler, filters
 
 from commands import (
     cmd_add,
+    cmd_admin,
     cmd_bounty,
     cmd_delete,
     cmd_edit,
@@ -41,6 +42,7 @@ def build_app() -> Application:
     app.add_handler(CommandHandler("delete", cmd_delete))
     app.add_handler(CommandHandler("track", cmd_track))
     app.add_handler(CommandHandler("untrack", cmd_untrack))
+    app.add_handler(CommandHandler("admin", cmd_admin))
 
     app.add_handler(MessageHandler(filters.COMMAND, cmd_help))
 
@@ -56,6 +58,7 @@ async def post_init(app: Application) -> None:
             ("edit", "Edit a bounty"),
             ("track", "Track a bounty"),
             ("untrack", "Stop tracking"),
+            ("admin", "Admin management"),
             ("help", "Show help"),
         ]
     )