There are a few steps to follow when creating a new command.
First, add your code to bot/handlers.py and register your new command in the HANDLERS constant at the end of the file.
You must also update the /help command to include the new command.
You need to add the command in the Bot Manual Settings and set up the full, updated command list in your Telegram bot (by talking to BotFather).
Edit the Functional Testing to include the new command.