doc: Add support documentation (#450)

Author: remyleone

.github/SUPPORT.md

@@ -1,5 +1,12 @@
 # Support
 
-Terraform is a mature project with a growing community. There are active, dedicated people willing to help you through various mediums.
+## Terraform help
+
+Terraform is a mature project with a growing community.
+There are active, dedicated people willing to help you through various mediums.
 
 Take a look at those mediums listed at https://www.terraform.io/community.html
+
+## Scaleway provider
+
+Feel free to come ask for help on our [Community Slack](https://slack.scaleway.com/) (#opensource)