Merge pull request #56 from mxssl/chore/update-contributing-guidelines

chore: update contributing guidelines

Author: mxssl

CONTRIBUTING.md

@@ -2,12 +2,18 @@
 
 ## Adding to this list
 
-Please ensure your pull request adheres to the following guidelines:
+Please make sure your pull request follows these guidelines:
 
-- Search existing articles before adding a new one, as yours may be a duplicate.
-- Make sure the article is useful before submitting.
-- Use the following format: `- [] [title](link)`
-- Link additions should be added to the bottom of the relevant category.
+- Search the existing resources before adding a new one to avoid duplicates.
+- Add resources that are directly relevant to SRE interview preparation and
+  provide practical depth, clear explanations, or credible reference material.
+  Avoid generic career advice, shallow summaries, or resources that are only
+  loosely related to SRE work.
+- Do not submit purely promotional links. If you are affiliated with a resource,
+  disclose that in the pull request and explain why the resource is high quality
+  and relevant to SRE interview preparation.
+- Use the following format: `- [ ] [title](link)`
+- Add new links to the bottom of the relevant category.
 - New categories or improvements to the existing categorization are welcome.
 - Check your spelling and grammar.