Update app.py

app.py

@@ -62,6 +62,9 @@ def train_and_forecast(
     print(date_range)
     new_df = df.reindex(date_range)
     new_df = new_df.interpolate(method='spline', order=2)
+    new_df.reset_index(inplace=True)
+    new_df.columns = ['ds', 'y']
+
     # trying this hack to fix pandas beginMonth stuff
     buffer = io.BytesIO()
     new_df.to_csv(buffer, index=False)