start jenkins ubuntu code example

Example: install jenkins on ubuntu

## Install java
sudo apt update && sudo apt install openjdk-8-jdk -y

## Install Jenkins
wget -q -O - https://pkg.jenkins.io/debian-stable/jenkins.io.key | sudo apt-key add -

sudo sh -c 'echo deb https://pkg.jenkins.io/debian-stable binary/ > \
    /etc/apt/sources.list.d/jenkins.list'

sudo apt-get update && sudo apt-get install jenkins -y