let users add their inventory

[svidgen]

As users build a deck, let them mark cards off as already owned in some way. (Ideally, being able to specify a quantity owned as well.)

Down the road ... maybe be able to limit searches to "cards I own" and "cards my friends or I own" ...

[svidgen]

Consider just hooking into this service initially: https://www.echomtg.com/plans/

And then consider an internal inventory solution down the road for non-trader types who just want to limit card suggestions to those cards they already own.