Auth:
POST /api/auth/loginPOST /api/auth/registerGET /api/auth/mePOST /api/auth/logout
Groups:
GET /api/groupsPOST /api/groupsGET /api/groups/:idPUT /api/groups/:idDELETE /api/groups/:idPOST /api/groups/:id/membersDELETE /api/groups/:id/members/:memberIdGET /api/groups/:id/balances
Expenses:
GET /api/groups/:id/expensesPOST /api/groups/:id/expensesGET /api/expenses/:idPUT /api/expenses/:idDELETE /api/expenses/:idPOST /api/groups/:id/settle
Currency:
GET /api/currency/ratesGET /api/currency/convert?amount=X&from=USD&to=EUR