Handle amount in import and display

postgres/conn.go

@@ -43,3 +43,13 @@ func (tx Transaction) GetAmount() float64 {
 	}
 	return amount
 }
+
+func (tx Transaction) GetAmountString() string {
+	amount := tx.GetAmount()
+	return fmt.Sprintf("%.2f", amount)
+}
+
+func (tx Transaction) GetPositive() bool {
+	amount := tx.GetAmount()
+	return amount >= 0
+}