Add research notice

... so contributors are aware I'm carrying out research over the next year. Let me know if there's a better place to put this! 

@glyg is aware of this :)

README.md

@@ -206,3 +206,14 @@ The tyssue library stemed from a refactoring of the `leg-joint` code used in [mo
 [Tamulonis2013]: Tamulonis, C. Cell-based models. (Universiteit ven Amsterdam, 2013). doi:10.1177/1745691612459060.
 
 [Tlili2013]: Tlili,S. et al. Mechanical formalism for tissue dynamics. 6, 23 (2013).
+
+## Research notice
+Please note that this repository is participating in a study into sustainability
+ of open source projects. Data will be gathered about this repository for
+ approximately the next 12 months, starting from June 2021.
+
+Data collected will include number of contributors, number of PRs, time taken to
+ close/merge these PRs, and issues closed.
+
+For more information, please visit
+[our informational page](https://sustainable-open-science-and-software.github.io/) or download our [participant information sheet](https://sustainable-open-science-and-software.github.io/assets/PIS_sustainable_software.pdf).