add KUBERMATIC_TOKEN info and knonw limitations (#42)

* add KUBERMATIC_TOKEN info and knonw limitations

* add missing char

website/docs/index.html.markdown

@@ -31,7 +31,8 @@ resource "kubermatic_project" "project" {
 The provider tries to read a token from `~/.kubermatic/auth` by default,
 it is possible to change the token location by setting `token_path` argument.
 Another way of authentication is to pass `KUBERMATIC_TOKEN` env or set `token` param,
-the last option is not recommended due to possible secret leaking.
+the last option is not recommended due to possible secret leaking. A new token can get
+generated at the KKP UI, see [KKP Documentation > Using Service Accounts](https://docs.kubermatic.com/kubermatic/v2.19/architecture/concept/kkp-concepts/service_account/using_service_account/).
 
 ## Argument Reference
 
@@ -43,3 +44,14 @@ The following arguments are supported:
 * `log_path` - (Optional) Location to store provider logs. Can be sourced from `KUBERMATIC_LOG_PATH`
 * `debug` - (Optional) Set logger to debug level. Can be sourced from `KUBERMATIC_DEBUG`.
 * `development` - (Optional) Run development mode. Useful only for contributors. Can be sourced from `KUBERMATIC_DEV`.
+
+## Known Limitations
+
+Please be aware the Kubermatic terraform provider isn't feature complete at the moment and is under development. 
+Currently only the following cloud providers are supported with limited functionality (for more details take a look
+at the [examples](https://github.com/kubermatic/terraform-provider-kubermatic/tree/master/examples)):
+* AWS
+* Azure
+* OpenStack
+
+If you interested in new features or want to contribute, please take a look at the [open issues](https://github.com/kubermatic/terraform-provider-kubermatic/issues) or the [CONTRIBUTING.md](https://github.com/kubermatic/terraform-provider-kubermatic/blob/master/CONTRIBUTING.md).