Merge pull request #5124 from voxel51/docs/smtp-config

[docs] SMTP config

docs/source/teams/pluggable_auth.md

@@ -44,8 +44,6 @@ and [OAuth2](https://oauth.net/2/).
 
 <!-- TODO: Enumerate what connection types are supported. -->
 
-> NOTE: invitations to onboard users are not supported in internal mode.
-
 (super-admin-ui)=
 
 ## Super Admin UI
@@ -72,6 +70,56 @@ screen, and provide the `FIFTYONE_AUTH_SECRET` to login.
 
 (identity-providers)=
 
+### New User Invitations
+
+As of FiftyOne Teams 2.1.0, onboarding new users can be done via invitation
+links. To do so, "Enable invitation" must be toggled on in the Organizations
+section of the [Super Admin UI](#super-admin-ui).
+
+![Enable Invitations](/images/teams/cas/org_enable_invitations.png)
+
+This allows creating invitation links in [internal mode](#internal-mode) that
+can be manually sent to users. When those users click the links, they will be
+added to the Organization and prompted to log in.
+
+As of FiftyOne Teams 2.2.0, these invitation links can be automatically sent
+via an email through a configured SMTP server. This provides similar
+functionality to [legacy mode](#legacy-mode) email invitations, but without the
+need for Auth0 or any other external connections beyond the SMTP server itself.
+
+> **NOTE:** Unless the deployment is a Managed Deployment, users must provide
+> their own SMTP server to use in [internal mode](#internal-mode). This new
+> functionality provides a way to authenticate and communicate with your
+> existing mail server.
+
+To do so, "Send email invitations" must be toggled on in the Organizations
+section of the [Super Admin UI](#super-admin-ui)
+
+![Send email invitations](/images/teams/cas/org_send_email_invitations.png)
+
+To configure your SMTP connection, navigate to the SMTP section of the
+[Super Admin UI](#super-admin-ui)
+
+![SMTP Config](/images/teams/cas/SMTP_config.png)
+
+A notification at the top of the menu will inform if an SMTP configuration is
+already saved. Currently, only one SMTP configuration can be saved per
+Organization.
+
+Select the appropriate type of authentication for your SMTP server and fill out
+the associated fields. When you save the configuration, FiftyOne Teams will do
+a preliminary check to ensure that the SMTP server is reachable at the host
+provided. The configuration will not save otherwise.
+
+Additionally, users can enter a valid email address and click Send Test Email
+to test the connection.
+
+![SMTP Config test email](/images/teams/cas/SMTP_config_test_email.png)
+
+> **NOTE:** Emails and an SMTP connection are not required to use invitations.
+> Invitation links can still be generated and manually distributed without an
+> SMTP configuration.
+
 ## Identity Providers (IdP)
 
 In [internal mode](#internal-mode), use the CAS REST API or Super Admin UI to