Introducing OpenCost Guru on Gurubase.io (#2974)

Signed-off-by: Kursat Aktas <kursat.ce@gmail.com>

README.md

@@ -1,5 +1,6 @@
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![OpenSSF Best Practices](https://www.bestpractices.dev/projects/6219/badge)](https://www.bestpractices.dev/projects/6219)
+[![Gurubase](https://img.shields.io/badge/Gurubase-Ask%20OpenCost%20Guru-006BFF)](https://gurubase.io/g/opencost)
 
 ![](./opencost-header.png)