Add automated tests badge (#38)

Author: Alexandre

.github/workflows/push.yml

@@ -10,7 +10,7 @@ jobs:
       - name: Unit tests
         run: docker exec -i app make test-unit
       - name: Sleep
-        run: sleep 30
+        run: sleep 20
       - name: Integration tests
         run: docker exec -i app make test-integration
       - name: UI tests

README.md

@@ -1,6 +1,7 @@
 # Practical Test Pyramid with Go
 
 [![GoDoc](https://godoc.org/github.com/alr-lab/practical-test-pyramid-go?status.svg)](https://godoc.org/github.com/alr-lab/practical-test-pyramid-go)
+[![Automated tests](https://github.com/alr-lab/practical-test-pyramid-go/actions/workflows/push.yml/badge.svg)](https://github.com/alr-lab/practical-test-pyramid-go/actions/workflows/push.yml)
 [![Go Report Card](https://goreportcard.com/badge/github.com/alr-lab/practical-test-pyramid-go)](https://goreportcard.com/report/github.com/alr-lab/practical-test-pyramid-go)
 
 [_Practical Test Pyramid with Go_][ptp-page] is an experiment to work with