Set correct variable name in docs (#257)

Tenancy mode is set via SOURCEBOT_TENANCY_MODE, not SOURCEBOT_AUTH_ENABLED

Author: Audiotape-2

docs/self-hosting/more/tenancy.mdx

@@ -6,7 +6,7 @@ sidebarTitle: Multi tenancy
 <Warning>If you're switching from single-tenant mode, delete the Sourcebot cache (the `.sourcebot` folder) before starting.</Warning>
 <Warning>[Authentication](/self-hosting/more/authentication) must be enabled to enable multi tenancy mode</Warning>
 Multi tenancy allows your Sourcebot deployment to have **multiple organizations**, each with their own set of members and repos. To enable multi tenancy mode, define an environment variable
-named `SOURCEBOT_AUTH_ENABLED` and set its value to `multi`. When multi tenancy mode is enabled:
+named `SOURCEBOT_TENANCY_MODE` and set its value to `multi`. When multi tenancy mode is enabled:
 
 - Any members or repos that are configured in an organization are isolated to that organization
 - Members must be invited to an organization to gain access 
@@ -24,4 +24,4 @@ the organization will be the Owner.
 
 To switch between organizations, press the drop down on the top left of the navigation menu. This also provides an option to create a new organization:
 
-![Org switching](/images/org_switch.png)
+![Org switching](/images/org_switch.png)