A long-running `rails console --sandbox` could cause a database server
to become out-of-memory as it's holding on to changes that happen on the
database.
Given that it's common for Ruby on Rails application with huge
traffic to have separate write database and read database, we should
allow the developers to disable this sandbox option to prevent someone
from accidentally causing the Denial-of-Service on their server.
Running the `console` and `dbconsole` commands with a regular argument
as the environment's name automatically expand it to match an existing
environment (e.g. dev for development).
This feature wasn't available using the `--environment` (a.k.a `-e`)
option.
