feat: credit by user calculations

src/main/java/com/application/munera/services/ExpenseService.java

@@ -29,6 +29,9 @@ public class ExpenseService {
         return repository.findDebtorsExpensesByPersonId(person.getId());
     }
 
+    public Collection<Expense> findCreditByUser(final Person person) {
+        return repository.findCreditorsExpensesByPersonId(person.getId());
+    }
     public List<Expense> findAll() {return repository.findAll();}
 
     public Expense update(Expense entity) {

src/main/java/com/application/munera/services/PersonService.java

@@ -54,4 +54,8 @@ public class PersonService {
     public BigDecimal calculateDebt(final Person person){
         return this.expenseService.findDebtByUser(person).stream().map(Expense::getCost).reduce(BigDecimal.ZERO, BigDecimal::add);
     }
+
+    public BigDecimal calculateCredit(final Person person) {
+        return this.expenseService.findCreditByUser(person).stream().map(Expense::getCost).reduce(BigDecimal.ZERO, BigDecimal::add);
+    }
 }

src/main/java/com/application/munera/views/expenses/PeopleView.java

@@ -70,6 +70,7 @@ public class PeopleView extends Div implements BeforeEnterObserver {
         grid.addColumn(Person::getLastName).setHeader("Last Name").setSortable(true);
         grid.addColumn(Person::getEmail).setHeader("Email").setSortable(true);
         grid.addColumn(personService::calculateDebt).setHeader("Debt").setSortable(true);
+        grid.addColumn(personService::calculateCredit).setHeader("Credit").setSortable(true);
         grid.getColumns().forEach(col -> col.setAutoWidth(true));
         grid.setItems(query -> personService.list(
                         PageRequest.of(query.getPage(), query.getPageSize(), VaadinSpringDataHelpers.toSpringDataSort(query)))