we want to make it easier for rails users to setup sentry, see
https://fly.io/docs/reference/sentry/#ruby-on-rails
and
https://github.com/getsentry/sentry-wizard
- add new rake command like
bundle exec sentry:setup
- auto create default initializer
- some questions TBD (see sentry-wizard and how they do it)
- DSN
- enable performance
- enable profiling