Wrap some errors

server/ynab-import.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"fmt"
 	"net/http"
 
 	"git.javil.eu/jacob1123/budgeteer/postgres"
@@ -26,12 +27,12 @@ func (h *Handler) importYNAB(c echo.Context) error {
 
 	transactionsFile, err := c.FormFile("transactions")
 	if err != nil {
-		return err
+		return fmt.Errorf("get transactions: %w", err)
 	}
 
 	transactions, err := transactionsFile.Open()
 	if err != nil {
-		return err
+		return fmt.Errorf("open transactions: %w", err)
 	}
 
 	err = ynab.ImportTransactions(c.Request().Context(), transactions)
@@ -41,12 +42,12 @@ func (h *Handler) importYNAB(c echo.Context) error {
 
 	assignmentsFile, err := c.FormFile("assignments")
 	if err != nil {
-		return err
+		return fmt.Errorf("get assignments: %w", err)
 	}
 
 	assignments, err := assignmentsFile.Open()
 	if err != nil {
-		return err
+		return fmt.Errorf("open assignments: %w", err)
 	}
 
 	err = ynab.ImportAssignments(c.Request().Context(), assignments)