Create a RIT ADD WORKSPACE command

[GuillaumeFalourd]

What would you like to be added:

A core command to add a new workspace.

Why is this needed:

Today, you can only add a new workspace when creating a formula.

However, there is a scenario when an user may need to update a formula without having the workspace configured locally, which is when cloning a new repository to update a formula inside it.

As it is today, if an user clones a repository to edit a formula inside it, he won't be able to test it locally without adding a new formula to the cloned repository, to turn it a workspace (which is strange).

• Check this box if this issue needs a documentation update

[henriquemoraeszup]

Flags added name -> workspace name, path -> workspace path