Fixed broken links (#220)

CONTRIBUTING_GUIDELINES.md

@@ -1,8 +1,8 @@
 # Contributing Guidelines
 * You can join our [slack channel](http://systers.io/slack-systers-opensource/).  Each active repo has its own channel to direct questions to (for example #powerup or #portal).  
-* Remember that this is an inclusive community, committed to creating a safe, positive environment.  See the full [Code of Conduct](systers.io/code-of-conduct.html).
+* Remember that this is an inclusive community, committed to creating a safe, positive environment.  See the full [Code of Conduct](http://www.systers.io/code-of-conduct.html).
 ## General Guidelines
-* If you’re just getting started work on an issue labeled “First Timers Only” in any project. Additional resources are available on our [website](systers.io).
+* If you’re just getting started work on an issue labeled “First Timers Only” in any project. Additional resources are available on our [website](http://www.systers.io).
 * In an active repository (not an archived one), choose an open issue from the issue list, claim it in the comments, and a maintainer will assign it to you.  
 * After approval you must make continuous notes on your progress in the issue while working.  If there is not at least one comment every 3 days, the maintainer can reassign the issue.
 * When sending a PR have an appropriate title referencing the issue which it solves. Add “fixes #<issue-number>” in the commit body, so that when the PR gets merged, the issue gets closed automatically. Do not do this if the PR solves only a part of the issue. See more information on commit guidelines [here](https://udacity.github.io/git-styleguide/).