Feature: Subtract already-owned ingredients from shopping list

[langston-barrett]

This would be a two-part enhancement. Please correct me if any of my observations are mistaken.

It seems to me that shop simply concatenates the list of ingredients of the desired recipes. In the case that I'm making two recipes, each of which calls for limes, it seems that I'll get two lines in the output, each with different quantities of limes. So enhancement (1) would be to smartly combine the ingredients with identical, or better, inter-convertible units.

Once this is done, herms could also take in a list (from a file?) of ingredients the user already has, and remove them from the shopping list (or reduce the quantity in the list by the relevant amount).

I would be very happy to implement this!

[LuxMiranda]

Seems like an awesome idea!

[langston-barrett]

Enhancement (1) as described above is implemented in #71.

[langston-barrett]

I have a branch with this feature in the works, just waiting on #76:

https://github.com/JackMiranda/herms/compare/master...siddharthist:pantry-rebased?expand=1