Update TODO
Disallow adding beneficiaries after any one of them has paid
Add Purchase.settle_debt
Fix indentation
Add purchase.views.debts
Add purchase.views.show_debts
Add purchase.views.settle_debts
Add debts.html template to purchases
Add debts.html to urls
Link to debt pages from the summary
Update TODO
Reimplement Purchase.add_benefit
Hide beneficiary addition form for purchases with partially piad off debts
Adjust Purchase.settle_debt
Update TODO
Add link to summary page from the debts page
Dump new initial data for purchases app