Enhancement in the source code switch - case

**Describe the solution you'd like**
Adding commands became a hurdle with `switch - case`.
I would be nice to replace it with `if - else if`

Here is the file to fix:
https://github.com/reacli/cli/blob/develop/bin/reacli.js#L22

**Additional context**
Related to: 
- https://github.com/reacli/cli/issues/36
- https://github.com/reacli/cli/pull/72
