Add link to altair slack
@@ -207,7 +207,7 @@ visualization.
We are also seeking contributions of additional Jupyter notebook-based examples
in our separate GitHub repository: https://github.com/altair-viz/altair_notebooks.
-The altair users mailing list can be found at https://groups.google.com/forum/#!forum/altair-viz
+The altair users mailing list can be found at https://groups.google.com/forum/#!forum/altair-viz. If you are working on Altair, you can talk to other developers in the `#altair` channel of the [Vega slack](https://bit.ly/join-vega-slack).
## Whence Altair?
