Feature request: ability to run garden with extra aliases

[teodorlu]

Thanks again for garden, it's a pleasure to use.

I'm working on a library alongside my Garden app, using a :local/root dependency locally, and a Git dep in production. Currently I comment in/out the coordinates, and avoid committing the :local/root coordinate.

If garden run allowed me to select additional aliases, for example

garden run --aliases :dev

, that would help me a lot!