Update docker-compose.yml

[vikaskedia]

removed the volume mount option from rocketchat since the files are stored inside mongodb

[rodrigok]

LGTM

[engelgabriel]

They can be stored on the filesystem, the commented lines are there for reference :)

[miscs]

How can file uploads be stored on the filesystem?
In the admin-interface there is no property to configure this and all files are saved in mongo even with the volume mount options in docker.

Thanks for any hints!

[engelgabriel]

Currently only the avatars can be saved on the FS, but this #2435 added the option to send any uploaded file to S3 too. On the next release we will add the unify the methods for Avatars and Uploads.