feat: add invoice category

This is useful for reporting.

weblate_web/invoices/admin.py

@@ -45,8 +45,8 @@ class InvoiceItemAdmin(admin.TabularInline):
 class InvoiceAdmin(admin.ModelAdmin):
     date_hierarchy = "issue_date"
     autocomplete_fields = ("customer",)
-    list_display = ("number", "kind", "customer", "total_amount")
-    list_filter = ["kind"]
+    list_display = ("number", "kind", "category", "customer", "total_amount")
+    list_filter = ["kind", "category"]
     search_fields = (
         "customer__name",
         "number",

weblate_web/invoices/migrations/0008_invoice_category.py

@@ -0,0 +1,25 @@
+# Generated by Django 5.1.2 on 2024-10-23 13:36
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("invoices", "0007_invoice_number"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="invoice",
+            name="category",
+            field=models.IntegerField(
+                choices=[
+                    (1, "Hosting"),
+                    (2, "Support"),
+                    (3, "Development"),
+                    (4, "Donation"),
+                ],
+                default=1,
+            ),
+        ),
+    ]

weblate_web/invoices/models.py

@@ -80,6 +80,13 @@ class InvoiceKind(models.IntegerChoices):
     QUOTE = 90, "Quote"
 
 
+class InvoiceCategory(models.IntegerChoices):
+    HOSTING = 1, "Hosting"
+    SUPPORT = 2, "Support"
+    DEVEL = 3, "Development"
+    DONATE = 4, "Donation"
+
+
 class Discount(models.Model):
     description = models.CharField(max_length=200, unique=True)
     percents = models.IntegerField(
@@ -109,6 +116,9 @@ class Invoice(models.Model):
     issue_date = models.DateField(default=datetime.date.today)
     due_date = models.DateField(blank=True)
     kind = models.IntegerField(choices=InvoiceKind)
+    category = models.IntegerField(
+        choices=InvoiceCategory, default=InvoiceCategory.HOSTING
+    )
     customer = models.ForeignKey("payments.Customer", on_delete=models.deletion.PROTECT)
     customer_reference = models.CharField(max_length=100, blank=True)
     discount = models.ForeignKey(