update contributing guide about PR merging (#88)

* update contributing guide about PR merging

* update readme with links to docs

Author: TheJolman

.github/CONTRIBUTING.md

@@ -40,3 +40,8 @@ Don't be afraid to ask for help with anything on this project. DMs are open!
 - The Copilot PR review is a useful feature - it often catches easy to miss
   copy-paste errors, spelling/grammar mistakes, and other things. Be cautious
   though - it can make mistakes, and always validate the issues it finds.
+- Only *squash merging and rebase merging* into main are allowed. Don't worry
+  about this too much, but if you don't know which to choose:
+  - Choose a squash merge if the individual commits in the PR don't matter very
+    much and/or the change is relatively atomic.
+  - Choose a rebase merge if the individual commits in the PR do matter.

README.md

@@ -1,6 +1,6 @@
 # api.acmcsuf.com
 
-ACM at CSUF club API for managing events, announcements, forms, and other services! See the `developer-docs/` directory for more information on using and contributing to this project.
+ACM at CSUF club API for managing events, announcements, forms, and other services! Keep reading for information on setting up this project locally, and see the [contributor guide](./.github/CONTRIBUTING.md) and [`developer-docs/`](./developer-docs) for more information on using and contributing to this project.
 
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