@CaioDA Just disable them from the admin control panel. Options > Disable then Save.
Is it really that simple? Now I'm embarrassed... But, going along with what @planner said and @psychobunny pointed out, this is a very developer centered forum software with an initially steep learning curve. It's not quite plug and play. I recommend something like Foundation's Joyride to introduce new users to the system.
Update: But currently, there is no way to remove them completely (unless a forum restart is required or override them). That's a feature I'd love to see.
@julian @MatthewHawley Not sure if you got this working or not but you need to specify the application you are adding the addon to:
heroku addons:add redistogo:nano -a myapp
You can also login into the heroku control panel, choose the "Resources" section of your app, click the "Get Add-ons" link and add it there. Terminal is much easier though.