added new problem

[Ashasindhu]

Issue Number:

This submission will close the issue #44

Submissions Checklist:

• [x] Have you followed the guidelines in CONTRIBUTING.md?
• [x] Have you checked there aren't other open Pull Requests for the same hackerrank problem?
• [x] Have you successfully submitted your code in hackerrank?
• [x] Is your file name exactly same as the problem name of hackerrank, followed by the proper extension?
• [x] Have you ensured that you have put the files in appropriate folders? (Folders are made according to the subdomain of hackerrank practice problems).

Hacktoberfest Contributor:

• [x] Are you a hacktoberfest contributor?

Hackerrank Problem Link:

https://www.hackerrank.com/challenges/java-string-reverse/problem?isFullScreen=true

Submitted Hackerrank Solution Link:

https://www.hackerrank.com/challenges/java-string-reverse/submissions/code/293570599

Any other changes you made or something you would like to mention?

NA