Add status badges to README (#22)

.github/workflows/tests.yml

@@ -1,11 +1,11 @@
 ---
+name: Gauge specs
 on:  # yamllint disable-line rule:truthy
   # Run the tests on every push, and also at 3am every night
   push:
   schedule:
     - cron: '0 3 * * *'  # * is a special character in YAML so you have to quote this string
 
-name: Gauge
 jobs:
   tests:
     name: ${{ matrix.gauge-env }} server

README.md

@@ -1,5 +1,13 @@
 # gauge-openapi-example
 
+[![Gauge Badge](https://gauge.org/Gauge_Badge.svg)](https://gauge.org)
+
+[![Gauge](https://github.com/agilepathway/gauge-openapi-example/workflows/Gauge%20specs/badge.svg)](https://github.com/agilepathway/gauge-openapi-example/actions?query=workflow%3A%22Gauge+specs%22%3Apush+branch%3Amaster)
+[![reviewdog](https://github.com/agilepathway/gauge-openapi-example/workflows/reviewdog/badge.svg)](https://github.com/agilepathway/gauge-openapi-example/actions?query=workflow%3Areviewdog+event%3Apush+branch%3Amaster)
+[![License](https://img.shields.io/github/license/agilepathway/gauge-openapi-example?color=blue)](LICENSE)
+
+[![OpenAPI Validator](https://validator.swagger.io/validator?url=https://raw.githubusercontent.com/agilepathway/gauge-openapi-example/master/openapi.yaml)](./openapi.yaml)
+
 Example of how [Gauge](https://gauge.org/) and [OpenAPI](https://www.openapis.org/about) play nicely
 together to produce [living documentation](https://www.infoq.com/articles/book-review-living-documentation/) for APIs.