Remember previous ruby before auto-switch

[terlar]

If you don't have a global .ruby-version file and are using auto-switch. You will always end up with the last projects ruby version when you switch folders.

One way to solve this problem is to have some kind of memory which ruby version was used before the auto-switch. This could then allow to manually set a ruby version, switch to a project and the ruby switches and when you switch away from this project and you are back with the ruby version you manually switched to.