Fix rbt cloud up example

[joerg84]

The name parameter is required.
Should also be improved in the welcome email.

[aviator-app]

Current Aviator status

Aviator will automatically update this comment as the status of the PR changes.
Comment /aviator refresh to force Aviator to re-examine your PR (or learn about other /aviator commands).

This pull request is currently open (not queued).

How to merge

To merge this PR, comment /aviator merge or add the mergequeue-ready label.

---

See the real-time status of this PR on the Aviator webapp.

Use the Aviator Chrome Extension to see the status of your PR within GitHub.

[onelxj]

Hey @joerg84, thanks so much for taking the time to submit this PR! I'm curious about the context: how did you run into this issue?

Our expectation is that users run rbt commands from the directory containing their .rbtrc file, where the application name is already specified (like here:

reboot-hello/.rbtrc

Line 44 in aab3a94

cloud up --name=hello

).

With your proposed fix, if someone tries to run the command from a directory that already has a .rbtrc file with a name specified, they'll now see this error:

rbt cloud up --api-key=HMDKIGGQVS-IQFMSDKHONMYAYUPYUPP --name=hello
usage: rbt cloud up [-h] [--config=CONFIG] [--cloud-url=CLOUD_URL] --api-key=API_KEY --name=NAME [--dockerfile=DOCKERFILE] [--docker-build-arg=DOCKER_BUILD_ARG]
rbt cloud up: error: the flag '--name' was set multiple times; it can only be set once, including in the `.rbtrc` file

Could you share more about your use case? I'd love to understand what led to this situation and how we might improve the experience to prevent this kind of confusion in the future.