update readme

README.md

@@ -182,7 +182,7 @@ useful helper and plotting functions that are used in the sample notebooks.
 <td>N/A</td>
 </tr>
 <tr>
-<td><a href="https://www.apple.com/covid19/mobility">Apple</a> 
+<td><a href="https://www.apple.com/covid19/mobility">Apple</a>
     <a href="https://www.google.com/covid19/mobility/">Google</a>
     <a href="https://docs.google.com/spreadsheets/d/1zu9qEWI8PsOI_i8nI_S29HDGHlIp2lfVMsGxpQ5tvAQ/edit#gid=2102005060">BU</a>
 </td>
@@ -255,6 +255,15 @@ A collection of tweet-ids related to covid-19 from https://github.com/echen102/C
 - https://worldmap.harvard.edu/data/geonode:country_centroids_az8
 - https://wikidata.com (for population figures)
 
+
+### How is the data updated?
+
+Each morning an automatic pipeline is executed that fetches new data from each
+of the data sources. `renku` is then used to run whichever pipelines are
+necessary to update the pre-processed data and the rendered notebooks in order
+to reflect the changes in the data.
+
+
 ## Derived Dataset Summary
 
 <table class="table">