Enhance readme

[HuKeping]

Hi, does is make sense to add more detail about this project to the README. I want to know more about this project but hardly find a docs to begin with.

First question in my mind, what's the different with the OCI/image-tool?

Sorry I don't want to bother you guys @philips @runcom but I find you are the only members of github.com/container.

[rhatdan]

@runcom can we still some of the text from skopeo to enhance the README? The readme is rather lacking.

[runcom]

We could, I'll try to find some spare cycles to do this but if anyone want to contribute please do so

[rhatdan]

@cyphar did some decent write up in cri-o/cri-o#175 We could probably grab some of his content.

[HuKeping]

Thanks @rhatdan @runcom , I've got what I want in cri-o/cri-o#175 .

If we should still keep this issue open to track the updating of README?

[Crazykev]

+1 for a detailed README