feat: add business logic method

Author: barcellos-pedro

src/main/java/com/itau/transferencia/entities/Customer.java

@@ -62,10 +62,14 @@ public static boolean isSameAccount(Customer customer, Customer other) {
         return customer.getAccount().equals(other.getAccount());
     }
 
-    public boolean hasFundsToTransfer(BigDecimal amount) {
+    public boolean canTransfer(BigDecimal amount) {
         return this.getBalance().compareTo(amount) >= 0;
     }
 
+    public boolean cannotTransfer(BigDecimal amount) {
+        return !this.canTransfer(amount);
+    }
+
     public Long getId() {
         return id;
     }