[Documentation] Minor suggestions to the top README

[tachukao]

I have a couple of minor suggestions to the README, which I think can improve the documentation.

Intrdouction

• I think the introduction can benefit from a short description about what problem this repo is trying to solve.
• I really like the solution matrix, but I think it's assuming quite a bit of knowledge about what the three workflows (Local Container, Ray, and Kubeflow) are. This was made very clear in the paper with Figure 1 and the corresponding explanations. I think it might be worth putting that figure into the README and add some description about the use case from (initial exploration on local machine, further exploration on a local "unmanaged cluster", to launching on AWS/giant clusters).

Installation and Usage

• In the installation section, I think it would be good to be consistent with above and change "cluster" to "local cluster".

Others

• I think it would be helpful o add
  • a section pointing to the examples directory and
  • another section pointing to the JOSS paper.pdf

ref: JOSS review