Update to Rails 7 and Sqlite Default

[cmdrkeene]

Hi!

Rails 5 is very old now. Rails 7 would be a nice example.

It also ships with sqlite3 as the default database.

A "default" working example for this config would be welcome. Not everyone immediately wants to disregard the framework's default choice and immediately install a huge database. Every docker example online ignores sqlite3. It would be helpful to have both paths referenced from the docker site.

Thank you!

[sitarane]

I'm currently working on a rails 7 update.

I'll do both the sqlite version and the postgresql version.

https://github.com/sitarane/awesome-compose/blob/master/official-documentation-samples/rails/README.md

[sitarane]

Hmm. I'm thinking that here being a repo for Docker Compose, a Sqlite setup would make little sense as it would be single-container and not need compose at all.

[sitarane]

This PR attempts to solve this.

#377