Add badges

Author: IngeborgGjerde

README.md

@@ -1,3 +1,6 @@
+[![Pytest](https://github.com/IngeborgGjerde/graphnics/actions/workflows/main.yml/badge.svg)](https://github.com/IngeborgGjerde/graphnics/actions/workflows/main.yml)
+[![Docker image](https://github.com/IngeborgGjerde/graphnics/actions/workflows/docker-image.yml/badge.svg)](https://github.com/IngeborgGjerde/graphnics/actions/workflows/docker-image.yml)
+
 # Implementing network models in FEniCS
 
 The `graphnics` library solves network models using the finite element method. This is facilitated via the `FenicsGraph` class which is an extension of the `DiGraph` class in `networkx`. 
@@ -38,4 +41,4 @@ This code is currently being prepared for submission to JOSS, titled:
 
 *Graphnics: Combining networkx and FEniCS to solve network models* by Ingeborg Gjerde
 
-The paper draft can be found [here.](https://github.com/IngeborgGjerde/graphnics/blob/main/paper/joss.md)
+The paper draft can be found [here.](https://github.com/IngeborgGjerde/graphnics/blob/main/paper/joss.md)