chore: create contributing guidelines

Closes #177

Author: hperrin

CONTRIBUTING.md

@@ -0,0 +1,51 @@
+# Contributing
+
+Thank you for contributing!
+
+Svelte Material UI is a mature library, but is always looking for ways to improve. If you'd like to contribute, there are some guidelines you should know. First, let's get you started.
+
+## Setting up Your Dev Environment
+
+The first step is to fork the repo. Once you've got your own fork, check it out locally.
+
+```
+git clone git@github.com:yourusername/svelte-material-ui.git smui
+```
+
+Now you'll need lerna to get going. You can install it globally or you can run it with `npx`. I'm going to assume you want to install it globally.
+
+```
+npm install -g lerna
+```
+
+Now let's get the repo set up for development.
+
+```
+cd smui
+
+npm i
+
+# This will take a while
+lerna bootstrap
+
+cd site
+npm i
+```
+
+Now you're set up. If there are package-lock.json files updated after setting up, feel free to reset those changes. Run this in the site folder to start up the dev site.
+
+```
+npm run dev
+```
+
+Once that starts, you should be able to see the site at http://localhost:5000 and the site will refresh automatically when you make a change.
+
+## Commiting Changes
+
+SMUI uses Prettier to format code. You should use Prettier after you've edited a file before you commit it. You can set up your editor to run Prettier automatically when you save a file. Also, don't forget the Svelte Prettier plugin.
+
+SMUI uses [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) for commit messages, and Husky will lint your commit messages when you commit. Please follow the conventional commits format for you commit messages. Please also provide meaningful, informative messages.
+
+Once you've made your change, feel free to open a pull request.
+
+Happy coding, and thanks again for contributing!