Add invoice management

nummi/main/models.py

@@ -28,3 +28,13 @@ class Invoice(models.Model):
 
     def __str__(self):
         return f"{self.name}: {self.transaction}"
+
+    def delete(self, *args, **kwargs):
+        self.file.delete()
+        super().delete(*args, **kwargs)
+
+
+class InvoiceForm(ModelForm):
+    class Meta:
+        model = Invoice
+        fields = ["name", "file"]