Merge pull request #57 from dunglas/docs/treeware

docs: add treeware license

README.md

@@ -6,7 +6,8 @@ An open source gateway server which you can put on top of **any existing web API
 
 It supports [hypermedia APIs](https://restfulapi.net/hateoas/) but also any "legacy" API by documenting its relations [using OpenAPI](docs/gateway/openapi.md).
 
-[![GoDoc](https://godoc.org/github.com/dunglas/vulcain?status.svg)](https://godoc.org/github.com/dunglas/vulcain/gateway)
+[![Plant Tree](https://img.shields.io/badge/dynamic/json?color=brightgreen&label=Plant%20Tree&query=%24.total&url=https%3A%2F%2Fpublic.offset.earth%2Fusers%2Ftreeware%2Ftrees)](https://plant.treeware.earth/dunglas/vulcain)
+[![PkgGoDev](https://pkg.go.dev/badge/github.com/dunglas/vulcain/gateway)](https://pkg.go.dev/github.com/dunglas/vulcain/gateway)
 [![Build Status](https://github.com/dunglas/vulcain/workflows/CI/badge.svg)](https://github.com/dunglas/vulcain/actions)
 [![codecov](https://codecov.io/gh/dunglas/vulcain/branch/master/graph/badge.svg)](https://codecov.io/gh/dunglas/vulcain)
 [![Go Report Card](https://goreportcard.com/badge/github.com/dunglas/vulcain)](https://goreportcard.com/report/github.com/dunglas/vulcain)
@@ -208,6 +209,10 @@ The Vulcain Gateway Server is licensed under [AGPL-3.0](LICENSE). This license i
 
 For companies not wanting, or not able to use AGPL-3.0 licensed software, commercial licenses are also available. [Contact us for more information](mailto:kevin+vulcain@dunglas.fr).
 
+## Treeware
+
+This package is [Treeware](https://treeware.earth). If you use it in production, then we ask that you [**buy the world a tree**](https://plant.treeware.earth/dunglas/vulcain) to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats.
+
 ## Credits
 
 Created by [Kévin Dunglas](https://dunglas.fr). Sponsored by [Les-Tilleuls.coop](https://les-tilleuls.coop).