update readme for covid-19 tweet ID dataset

README.md

@@ -57,6 +57,12 @@ out.
 <td><code>data/covid-19-italy</code></td>
 <td>N/A</td>
 </tr>
+<tr>
+<td><a href="https://github.com/echen102/COVID-19-TweetIDs">Covid-19 tweet IDs</a></td>
+<td><a href="https://renkulab.io/projects/covid-19/covid-19-public-data/datasets/0fc08252-cb39-4b59-bc82-9b213ec0bec6/">covid-19-tweet-ids</a></td>
+<td><code>data/covid-19-tweet-ids</code></td>
+<td>N/A</td>
+</tr>
 </tbody>
 </table>
 
@@ -80,6 +86,10 @@ The [swiss cantonal data](https://github.com/openZH/covid_19) collected by the Z
 
 Detailed data compiled by the [Civil Protection of Italy](https://github.com/pcm-dpc/COVID-19).
 
+### Covid-19 related tweet IDs
+
+A collection of tweet-ids related to covid-19 from https://github.com/echen102/COVID-19-TweetIDs.
+
 ### General
 
 - https://data.worldbank.org/indicator/SP.POP.TOTL