how do i send in a file to roosterteeth for them to consider it for achievement horse
You email them.
And you also ask on their site - not here.
Protip: Google.
To quote this post from Bungie.net:
> You send it via email. The email address is horse@achievementhunter.com
>
> To submit your map, provide a short description of your map, your gamertag, a link to download the map, and a video of you completing the map.
>
> Then you wait to see if they accepted it.