Allow for multiple roster generation #4
Description
It would be nice if the user could supply a number of rosters to generate, and the solver would create that many rosters.
The way I think it works out is that every time the solver runs it adds new columns to the dataframe that indicates which players were selected in the previous roster(s). A constraint gets added that makes sure the new roster doesn't have the same selected player indexes as any of the previous rosters.