BMISS-2 Adding new "add" functionality

HelloGitHub functionality is getting bigger and stronger!!  We now support Add functionality.  This will enlighten math department.
 
[Jira BMISS-2 ](https://songchoe.atlassian.net/browse/BMISS-2 "Jira link")
[JenKin ](http://hrsabmistools.nih.gov:8000/ "JenKin")

## Description
#### HelloGitHub.java
Adding new function called Add() This function beautifully takes two integers and automatically add them amd prints out to the screen!!   This is the only we can print out to a screen as we cannot use Logger due to our department policy.


Status.
- [x] Jenkin is green
- [ ] Code Review is finished
- [ ] Manual testing is finished.