feat(contributing): add a contributing.md (#534)

resolve #533

Co-authored-by: Patrick DeVivo <patrick.devivo@gmail.com>

CONTRIBUTING.md

@@ -0,0 +1,58 @@
+# Contributing
+
+We'd love to have you as a contributor!
+This document outlines some general guidelines and instructions to follow when developing and submitting a PR.
+
+# Submitting a PR
+
+- We use [trunk based development](https://www.atlassian.com/continuous-delivery/continuous-integration/trunk-based-development) off of our `main` branch
+- Try to test your changes as much as possible before submitting a PR - ideally with tests defined in code
+- We use [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) to roughly categorize the work done in this repo
+- We try to use the habits described in [this article](https://thenewstack.io/6-pull-request-tricks-you-should-adopt-now-doordash/) when opening PRs 
+
+# Development
+
+To run MergeStat locally for development, we use `docker-compose` with some targets defined in the `Makefile`.
+
+## Running locally
+
+```sh
+# bring up all containers locally, building from the local source
+make dev
+```
+
+## Building changes
+
+```sh
+# build all images
+make docker-build
+
+# build the worker image
+make docker-build-worker
+
+# build the ui image
+make docker-build-ui
+
+# build the graphql service image
+make docker-build-graphql
+```
+
+## Cleaning Up
+
+```sh
+# stop running docker containers
+make docker-down
+
+# stop running docker containers and remove all networks/volumes (resets the state of the app)
+make docker-clean
+```
+
+## Running Tests
+
+```sh
+# run all the Go tests
+make test
+
+# run UI tests
+cd ui && npm run test
+```