Add GitHub action to automatically build and deploy website

.github/workflows/ci.yml

@@ -0,0 +1,18 @@
+name: Deploy
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  Deploy:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - run: mkdir -p ~/.ssh && echo "${{ secrets.DEPLOY_KEY }}" > ~/.ssh/id_rsa && chmod 400 ~/.ssh/id_rsa
+      - run: git config --global user.name "GitHub Actions" && git config --global user.email "actions@github.com"
+      - run: make
+      - run: git config --global url."https://${{ github.actor }}:${{ secrets.GITHUB_TOKEN }}@github.com/".insteadOf "https://github.com/"
+      - run: make deploy
+        if: ${{ github.ref == 'refs/heads/main' }}

README.md

@@ -1,5 +1,7 @@
 # Framework X website
 
+[![CI status](https://github.com/clue/framework-xwebsite/workflows/Deploy/badge.svg)](https://github.com/clue/framework-x-website/actions)
+
 Source code for the Framework X website.
 
 ## Build
@@ -37,3 +39,18 @@ the `live` branch like this:
 ```bash
 $ make deploy
 ```
+
+## Auto-Deployment
+
+The website can be automatically deployed via the GitHub Pages feature.
+
+Any time a commit is merged (such as when a PR is merged), GitHub actions will
+automatically build and deploy the website. This is done by running the above
+deployment script (see previous chapter).
+
+> Repository setup:
+> Note that this command will clone Framework X which is currently in early access.
+> We're using a read-only SSH deploy key for reading from this source repository.
+> Make sure the required `DEPLOY_KEY` secret is set in the repository settings on GitHub.
+> See [action documentation](https://github.com/JamesIves/github-pages-deploy-action#using-an-ssh-deploy-key-)
+> for more details.