included more details on searching for issues related to pull request

CONTRIBUTING.md

@@ -17,7 +17,7 @@ Please send a pull request with a tested solution or a pull request with a faili
 ### Issue tracker guidelines
-**Search** for similar entries before submitting your own, there's a good chance somebody else had the same issue or idea. Show your support with `:+1:` and/or join the discussion.
+**[Search](https://github.com/gitlabhq/gitlabhq/search?q=&ref=cmdform&type=Issues)** for similar entries before submitting your own, there's a good chance somebody else had the same issue or idea. Show your support with `:+1:` and/or join the discussion.
 * Only report issues for supported versions according to the [maintenance policy](MAINTENANCE.md)
 * Summarize your issue in one sentence (what goes wrong, what did you expect to happen)
@@ -42,6 +42,7 @@ We welcome pull request with improvements to GitLab code and/or documentation. T
 1. If you have multiple commits please combine them into one commit by [squashing them](http://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)
 1. Push the commit to your fork
 1. Submit a pull request
+2. [Search for issues](https://github.com/gitlabhq/gitlabhq/search?q=&ref=cmdform&type=Issues) related to your pull request and mention them in the pull request comments
 We will accept pull requests if: