yarn clear up ports code example

Example 1: how to close port 3000 running

### For Linux/Mac OS search (sudo) run this in the terminal:
$ lsof -i tcp:3000
$ kill -9 PID

### On Windows:
netstat -ano | findstr :3000
tskill typeyourPIDhere 

### change tskill for taskkill in git bash

Example 2: port already in use node js

sudo kill -9 $(sudo lsof -t -i:3000)