Getting started readme of framework/server suggests it can be inited with sb init -t server, but it can't

[ThaNarie]

Describe the bug
The documentation of the framework/server suggest to run sb init -t server.

https://github.com/storybookjs/storybook/tree/master/app/server
npx -p @storybook/cli sb init -t server

However, the server framework is currently not available in the sb cli.
https://github.com/storybookjs/storybook/blob/next/lib/cli/src/project_types.ts#L45-L59

To Reproduce
Steps to reproduce the behavior:

1. Open https://github.com/storybookjs/storybook/tree/master/app/server
2. Enter npx -p @storybook/cli sb init -t server in terminal
3. See error (server is not available)

Expected behavior
Either the documentation to show the correct install instructions, or the cli to include the server framework.

Additional context
Mentioned this to @shilman on Discord, he suggested to create an Issue to have look about what to do.

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[shilman]

¡Ay Caramba!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.3.0-beta.6 containing PR #13979 that references this issue. Upgrade today to the @next NPM tag to try it out!

npx sb upgrade --prerelease