Trigger to default fiat conversion on

Like all the other wallets

lnbits/core/migrations.py

@@ -684,3 +684,22 @@ async def m029_create_audit_table(db: Connection):
         );
         """
     )
+    
+async def m030_add_currency_to_wallet(db: Connection):
+    """
+    Setting currency to default is heavy, so easier just to add a trigger.
+    """
+    await db.execute(
+
+        """
+        CREATE TRIGGER IF NOT EXISTS set_default_currency
+        AFTER INSERT ON wallets
+        FOR EACH ROW
+        WHEN NEW.currency IS NULL
+        BEGIN
+            UPDATE wallets
+            SET currency = 'USD'
+            WHERE id = NEW.id;
+        END;
+        """
+    )