feat: internal code for automatic exchange rate fetching

app/apps/currencies/migrations/0007_exchangerateservice.py

@@ -0,0 +1,32 @@
+# Generated by Django 5.1.5 on 2025-02-02 20:35
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('currencies', '0006_currency_exchange_currency'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ExchangeRateService',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=255, unique=True, verbose_name='Service Name')),
+                ('service_type', models.CharField(choices=[('synth_finance', 'Synth Finance'), ('coingecko', 'CoinGecko')], max_length=255, verbose_name='Service Type')),
+                ('is_active', models.BooleanField(default=True, verbose_name='Active')),
+                ('api_key', models.CharField(blank=True, help_text='API key for the service (if required)', max_length=255, null=True, verbose_name='API Key')),
+                ('fetch_interval_hours', models.PositiveIntegerField(default=24, validators=[django.core.validators.MinValueValidator(1)], verbose_name='Fetch Interval (hours)')),
+                ('last_fetch', models.DateTimeField(blank=True, null=True, verbose_name='Last Successful Fetch')),
+                ('target_currencies', models.ManyToManyField(help_text='Select currencies to fetch exchange rates for. Rates will be fetched for each currency against their exchange_currency.', related_name='exchange_services', to='currencies.currency', verbose_name='Target Currencies')),
+            ],
+            options={
+                'verbose_name': 'Exchange Rate Service',
+                'verbose_name_plural': 'Exchange Rate Services',
+                'ordering': ['name'],
+            },
+        ),
+    ]