Add issue progression to section 2.1 in CONTRIBUTING.md (#3007)

CONTRIBUTING.md

@@ -314,6 +314,18 @@ In order to join [another project within Hack for LA](https://www.hackforla.org/
   * Complete steps in [**3.1 How to make a pull request**](#31-how-to-make-a-pull-request) to get your solution reviewed by the `website-merge` team
   * Once your pull request is merged, you can work on your next issue.
 
+Progress through issues with increasing complexity in the following order:
+  1. Good first issue
+  2. Good second issue
+  3. Small 
+  4. Medium 
+  5. Large
+
+The reasons for this progression are:
+  * The issues start out as being prescriptive and become less so as you gain more experience by working through increasingly complex issues.
+  * We are trying to teach you the team methodology through the issues themselves.
+  * It ensures you understand what we expect and the quality of contributions.
+
 All website team members are required to attend at least 1 team meeting in a week (held on Tuesdays, Thursdays and Sundays). In case, you are unable in any given week, you should reach out to the tech leadership team. Exceptions to this requirement may be provided on a case-by-case basis.
 
 Also, please let the tech leadership team know (through a slack message in the hfla-site channel as well as an @ mention in a comment of the issue that you would be working on) if you are planning to take a week off or a longer vacation.