Add short contribution section to primary README (#1157)

* Add short contribution section to primary README

* Update README.md

README.md

@@ -37,6 +37,15 @@ Extensive documentation is available [here](http://community.optimism.io/docs/).
 * [`ops`](./ops): Contains Dockerfiles for containerizing each service involved in the protocol,
 as well as a docker-compose file for bringing up local testnets easily
 
+## Contributing
+
+Read through [CONTRIBUTING.md](./CONTRIBUTING.md) for a general overview of our contribution process.
+
+### Good First Issues
+You can find good first issues by filtering for the ["good first issue" tag on our issues page](https://github.com/ethereum-optimism/optimism/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) or alternatively by taking a look at our [Good First Issues project board](https://github.com/orgs/ethereum-optimism/projects/23).
+If you'd like to tackle one of these issues, please leave a comment and [assign yourself to the issue](https://docs.github.com/en/issues/tracking-your-work-with-issues/assigning-issues-and-pull-requests-to-other-github-users#assigning-an-individual-issue-or-pull-request).
+This helps prevent two people accidentally working on the same task at the same time.
+
 ## Development Quick Start
 
 ### Dependencies