I'm not familiar enough with heroku to know how it handles gems, so I guess you'll have to read up on their stack/search in their help for an answer to that one.

On a more general note: not all of ChiliProject will work well on heroku, esp.: uploaded/saved files won't be persisted, i.e. you will lose them at each restart of the VM/dino your install runs on (if the part of the VM ChiliProject tries to save the files too is even writable…) and you won't be able to use git (and probably other) repos. I don't know what you're planning to use ChiliProject for, but you might want to be looking at other hosting options.

I was able to make it work by commenting out groups not needed like mysql sqlite and mysql2 in the gemfile. After this i was able to deploy.

I was thinking about using Amazon S3 CDN with redmine s3 plugin for file storage/attachments. The only thing missing then is what you mentioned, which is using git. I use github for my git repository, so I'm not sure if I'll use that part of chiliproject.