Finish the select expense and edit expense methods.
Add select category method.
Fix the loop exiting at the wrong place in Edit Expense and Edit Category causing @current_expense to be set to the wrong value.
Fix edit category method updating the description of current expense instead of current category and ui improve dialog.
Add expenses method to category class. Add ui to put an expense into one or more categories and be able to print out all categories associated with an expense, as well as all expenses associated with a category.
Finish details on ui method for adding expenses to categories and printing all expenses in a category, or vice versa.
Add general list method in ui to print either all expenses or all categories in the correct formats.
Finish implementing new list method in the rest of the ui, calling it instead of list_categories or list_expenses.