proper lesson on parallelism

[mr-c]

• using scatter
• using independent steps

[swzCuroverse]

@kinow It doesn't look like you added this yet? Did you have a place where you wanted it to go in the existing structure?

[kinow]

@kinow It doesn't look like you added this yet? Did you have a place where you wanted it to go in the existing structure?

Not, I haven't added it yet. I think it could be a top-leve lesson, like Using Containers, and Environment Variables. I think there's something already in the user guide about parallel execution of steps (could be in.. workflows? I think in some example where you have multiple steps and somewhere it says it will execute steps in parallel, not guaranteeing the order? If so might be worth linking to this new lesson).