npm and jest on mac. Command not found: jest

Hi,

I've started going through some exercises for JS (getting ready for interviews heheh)

And there they asked to have `jest` installed on my computer to run tests from those challenges
Oh, yes, jest looks very promising test framework to me. Finally my TDD skills from Ruby world can be applied to JS 😄

After following installation guide and trying to run tests, I was receiving error `$ command not found: jest`
Solution was to add `sudo` before command (which wasn't mentioned in guide 😞)

 sudo npm install -g jest 

Thanks