Deploy using GitHub actions (#131)

* github actions: only run on merge into master
* github actions: build PR using hugo

.github/workflows/build.yml

@@ -0,0 +1,46 @@
+---
+name: Build documentation
+# Setup and build files with hugo
+# https://github.com/peaceiris/actions-hugo
+# Deploy to GitHub pages
+# https://github.com/peaceiris/actions-gh-pages
+
+on: [push, pull_request]
+
+jobs:
+  deploy:
+    name: Build with Hugo
+    runs-on: ubuntu-18.04
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          # Fetch the Docsy theme
+          submodules: recursive
+          # Fetch all history for .GitInfo and .Lastmod
+          fetch-depth: 0
+
+      - name: Setup Hugo
+        uses: peaceiris/actions-hugo@v2
+        with:
+          hugo-version: "0.66.0"
+          extended: true
+
+      - name: Setup Node
+        uses: actions/setup-node@v1
+        with:
+          # NodeJS 12 is maintained until 2022-04-30
+          node-version: "12.x"
+
+      - name: Cache dependencies
+        uses: actions/cache@v1
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+
+      - name: Install npm project with a clean slate
+        run: npm ci
+
+      - name: Build and minify using Hugo
+        run: hugo --minify

.github/workflows/markdown-link-check.yml → .github/workflows/check-links.yml

@@ -1,4 +1,4 @@
-name: Check Markdown links
+name: Check links
 
 on: [push, pull_request]
 

.github/workflows/githubpages.yml → .github/workflows/deploy.yml

@@ -1,17 +1,14 @@
 ---
-name: github pages
+name: Deploy to GitHub pages
 # Setup and build files with hugo
 # https://github.com/peaceiris/actions-hugo
 # Deploy to GitHub pages
 # https://github.com/peaceiris/actions-gh-pages
 
-# XXX temporary for testing build in the PR
-on: [push, pull_request]
-# XXX to be used once confiremd it builds correctly
-# on:
-#   push:
-#     branches:
-#       - master
+on:
+  push:
+    branches:
+      - master
 
 jobs:
   deploy: