Add Zenodo archive badge

readme.rst

@@ -1,6 +1,8 @@
 Stellar Population Age Estimator
 ================================
 
+.. image:: https://zenodo.org/badge/79574563.svg
+   :target: https://zenodo.org/badge/latestdoi/79574563
 .. image:: https://travis-ci.org/benjaminrose/MC-Age.svg?branch=master
    :target: https://travis-ci.org/benjaminrose/MC-Age
    :alt: Test status on Travis-CI
@@ -61,4 +63,4 @@ This is building on the work from this poster_ from AAS 229 in January 2017.
 
 .. _poster: https://ui.adsabs.harvard.edu/#abs/2017AAS...22943402R/abstract
 
-If you use this project or reference the science from it, please cite the forthcoming scientific paper because the code currently does not have a DOI. For now linking to this Github repo is acceptable. DOIs and proper paper citations will come when the project is complete, early Fall 2018.
+If you use this project or reference the science from it, please cite the forthcoming scientific paper because the code currently does not have a DOI. For now linking to this Github repo is acceptable. DOIs and proper paper citations will come when the project is complete, early Fall 2018.