fix(javatarz#12): contriubtion guidelines - new package installation …

…instruction

CONTRIBUTING.md

@@ -34,6 +34,13 @@ Every PR/commit on this repository will be run through a build pipeline to ensur
 ### Your first contribution
 Unsure where to begin contributing to GHCL? You can start by looking through these
 
+### Adding any new package
+If you are adding any external package on project, please make you use `Pipenv’s Dependency Resolution Approach`
+
+eg: if you want to add redis package. Follow below steps
+`pipenv install redis`
+By doing this way, it'll update the Pipfile and Pipfile.lock.
+
 * [good first issue](https://github.com/javatarz/github-contribution-leaderboard/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22+sort%3Acomments-desc) - issues which should only require a few lines of code, and a test or two
 * [help-wanted issues](https://github.com/javatarz/github-contribution-leaderboard/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+wanted%22+sort%3Acomments-desc) - issues which should be a bit more involved than beginner issues