Broken link at Apache Zeppelin website's Contributions page

Whenever we raise a Pull Request for Apache Zeppelin, we are presented with a helping Questionnaire. One such question is below which points to Contribution guide.

### What is this PR for?
A few sentences describing the overall goals of the pull request's commits.
First time? Check out the contributing guide - https://zeppelin.apache.org/contribution/contributions.html

When you land on the webpage following the above link and click Community drop-down list on top menu and then click "Contributors" link, it throws error "The requested URL /contribution/community.html was not found on this server."