Previously you could skip encoding which would encode all parameters on an action as ASCII_8BIT, but after this change you can specify the param_encoding for any one parameter on an action in your controller. An example can be found here.
Sometimes you need to have a different default connection but aren't calling the connection with a block. An example is booting a console in reading mode. This PR adds the ability for a script to set a specific connection on boot while preserving the behaviour of connected_to for application code.
For multiple databases Rails attempts to generate the tasks by reading the database.yml before the Rails application is booted but there are some complex cases when this is not possible and Rails will simply issue a warning saying it couldn't infer the database tasks from the database.yml.