I noticed that when generating data migration in Rails 5, some people use rails db:migrate over rake db:migrate. Can someone explain the difference between the rails and the rake command in database migration? Does it mean the rake command is obsolete in Rails 5?
Rails core team decided to have consistency by enabling rails command to support everything that rake does. See PR Implement rake proxy for rails cli #22288
For example, in Rails 5, commands like db:migrate, db:setup, db:test etc., which are part of the rake command in Rails 4, are now being supported by the rails command. However, you can still choose to use rake to run those commands similar to how they were run in Rails 4. This is because the Rails community has introduced Rake Proxy instead of completely moving the command options from Rake to Rails.
What happens internally is that when rails db:migrate command is executed, Rails checks if db:migrate is something that rails natively supports or not. In this case, db:migrate is not natively supported by Rails, so Rails delegates the execution to Rake via Rake Proxy.
If you want to see all the commands that are supported by Rails in Rails 5, then you can get a long list of options by executing rails --help.