feat: add created_at time to links (#46)

closes #16

migrations.py

@@ -1,3 +1,6 @@
+from time import time
+
+
 async def m001_initial(db):
     """
     Creates an improved withdraw table and migrates the existing data.
@@ -132,3 +135,17 @@ async def m006_webhook_headers_and_body(db):
         "ALTER TABLE withdraw.withdraw_link ADD COLUMN webhook_headers TEXT;"
     )
     await db.execute("ALTER TABLE withdraw.withdraw_link ADD COLUMN webhook_body TEXT;")
+
+
+async def m007_add_created_at_timestamp(db):
+    await db.execute(
+        "ALTER TABLE withdraw.withdraw_link "
+        f"ADD COLUMN created_at TIMESTAMP DEFAULT {db.timestamp_column_default}"
+    )
+    # Set created_at to current time for all existing rows
+    await db.execute(
+        f"""
+        UPDATE withdraw.withdraw_link SET created_at = {db.timestamp_placeholder}
+        """,
+        (int(time()),),
+    )