update auth_database_name (#299)

* update auth_database_name

Missing add of $external, updated to match API docs.

* Adding a few more docs changes

link to privatelink example and add an example output to cluster.

Author: themantissa

website/docs/d/database_users.html.markdown

@@ -65,7 +65,12 @@ In addition to all arguments above, the following attributes are exported:
 * `project_id` - ID of the Atlas project the user belongs to.
 * `username` - Username for authenticating to MongoDB.
 * `roles` - List of user’s roles and the databases / collections on which the roles apply. A role allows the user to perform particular actions on the specified database. A role on the admin database can include privileges that apply to the other databases as well. See [Roles](#roles) below for more details.
-* `auth_database_name` - The user’s authentication database. A user must provide both a username and authentication database to log into MongoDB. In Atlas deployments of MongoDB, the authentication database is always the admin database.
+* `auth_database_name` - (Required) Database against which Atlas authenticates the user. A user must provide both a username and authentication database to log into MongoDB.
+Possible values include:
+  * `admin` if `x509_type` and `aws_iam_type` are omitted or NONE.
+  * `$external` if:
+    * `x509_type` is MANAGED or CUSTOMER, or
+    * `aws_iam_type` is USER or ROLE.
 
 * `x509_type` - X.509 method by which the provided username is authenticated.
 * `aws_iam_type` - The new database user authenticates with AWS IAM credentials. Default is `NONE`, `USER` means user has AWS IAM user credentials, `ROLE` - means user has credentials associated with an AWS IAM role.

website/docs/index.html.markdown

@@ -94,3 +94,9 @@ For more information on configuring and managing programmatic API Keys see the [
 [Request Features](https://feedback.mongodb.com/forums/924145-atlas?category_id=370723)
 
 [Support](https://docs.atlas.mongodb.com/support/) covered by MongoDB Atlas support plans, Developer and above.
+
+## Examples from the Community
+
+Have a good example you've created and want to share?  Let us know the details via an [issue](https://github.com/mongodb/terraform-provider-mongodbatlas/issues)
+
+[Example - AWS and Atlas PrivateLink with Terraform](https://github.com/nikhil-mongo/aws-atlas-privatelink)

website/docs/r/cluster.html.markdown

@@ -188,6 +188,13 @@ resource "mongodbatlas_cluster" "cluster-test" {
   auto_scaling_disk_gb_enabled = "false"
 }
 ```
+### Example - Return a Connection String
+```hcl
+output "plstring" {
+    value = lookup(mongodbatlas_cluster.cluster-test.connection_strings[0].aws_private_link_srv, aws_vpc_endpoint.ptfe_service.id)
+}
+//Example return string: plstring = mongodb+srv://cluster-atlas-pl-0.za3fb.mongodb.net
+```
 
 ## Argument Reference
 

website/docs/r/database_user.html.markdown

@@ -64,7 +64,12 @@ resource "mongodbatlas_database_user" "test" {
 
 ## Argument Reference
 
-* `auth_database_name` - (Required) The user’s authentication database. A user must provide both a username and authentication database to log into MongoDB. In Atlas deployments of MongoDB, the authentication database is always the admin database.
+* `auth_database_name` - (Required) Database against which Atlas authenticates the user. A user must provide both a username and authentication database to log into MongoDB.
+Accepted values include:
+  * `admin` if `x509_type` and `aws_iam_type` are omitted or NONE.
+  * `$external` if:
+    * `x509_type` is MANAGED or CUSTOMER, or
+    * `aws_iam_type` is USER or ROLE.
 * `project_id` - (Required) The unique ID for the project to create the database user.
 * `roles` - (Required) 	List of user’s roles and the databases / collections on which the roles apply. A role allows the user to perform particular actions on the specified database. A role on the admin database can include privileges that apply to the other databases as well. See [Roles](#roles) below for more details.
 * `username` - (Required) Username for authenticating to MongoDB.