Invoicing: Allow to show exchange rates based on sources/rules (#3122)

src/pretix/base/migrations/0232_exchangerate.py

@@ -0,0 +1,34 @@
+# Generated by Django 3.2.17 on 2023-02-14 15:34
+
+import django.core.serializers.json
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0231_auto_20230208_1546'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ExchangeRate',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False)),
+                ('source', models.CharField(max_length=100)),
+                ('source_date', models.DateField()),
+                ('updated', models.DateTimeField(auto_now=True)),
+                ('source_currency', models.CharField(max_length=3)),
+                ('other_currency', models.CharField(max_length=3)),
+                ('rate', models.DecimalField(decimal_places=6, max_digits=16)),
+            ],
+            options={
+                'unique_together': {('source', 'source_currency', 'other_currency')},
+            },
+        ),
+        migrations.AddField(
+            model_name='invoice',
+            name='foreign_currency_source',
+            field=models.CharField(max_length=100, null=True),
+        ),
+    ]