Add note about document generation and registry

Author: paultyng

README.md

@@ -1,11 +1,7 @@
 Terraform `null` Provider
 =========================
 
-- Website: https://www.terraform.io
-- [![Gitter chat](https://badges.gitter.im/hashicorp-terraform/Lobby.png)](https://gitter.im/hashicorp-terraform/Lobby)
-- Mailing list: [Google Groups](http://groups.google.com/group/terraform-tool)
-
-<img src="https://cdn.rawgit.com/hashicorp/terraform-website/master/content/source/assets/images/logo-hashicorp.svg" width="600px">
+See the documentation for this provider on the [Terraform Registry](https://registry.terraform.io/providers/hashicorp/null/latest/docs) for usage information.
 
 Maintainers
 -----------
@@ -34,14 +30,13 @@ $ cd $GOPATH/src/github.com/terraform-providers/terraform-provider-null
 $ make build
 ```
 
-Using the provider
-----------------------
-## Fill in for each provider
 
 Developing the Provider
 ---------------------------
 
-If you wish to work on the provider, you'll first need [Go](http://www.golang.org) installed on your machine (version 1.11+ is *required*). You'll also need to correctly setup a [GOPATH](http://golang.org/doc/code.html#GOPATH), as well as adding `$GOPATH/bin` to your `$PATH`.
+If you wish to work on the provider, you'll first need [Go](http://www.golang.org) installed on your machine (version 1.15+ is *required*).
+
+To generate the documentation, run `go generate` in the root of the codebase.
 
 To compile the provider, run `make build`. This will build the provider and put the provider binary in the `$GOPATH/bin` directory.