added Github Actions

.github/workflows/main.yml

@@ -0,0 +1,72 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - "main"
+  pull_request:
+
+jobs:
+  main:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/setup-node@v2
+        with:
+          # Choose your Node.js version here:
+          node-version: 15.x
+
+      # Re-use node_modules between runs until package.json or package-lock.json changes.
+      - name: Cache node_modules
+        id: cache-node_modules
+        uses: actions/cache@v2
+        with:
+          path: node_modules
+          key: node_modules-${{ hashFiles('package.json', 'package-lock.json') }}
+
+      # Re-use ~/.elm between runs until elm.json, elm-tooling.json or
+      # review/elm.json changes. The Elm compiler saves downloaded Elm packages
+      # to ~/.elm, and elm-tooling saves downloaded tool executables there.
+      - name: Cache ~/.elm
+        uses: actions/cache@v2
+        with:
+          path: ~/.elm
+          key: elm-${{ hashFiles('example/elm.json', 'example/elm-tooling.json', 'example/review/elm.json') }}
+
+      # Install npm packages, unless we restored them from cache.
+      # Since `npm ci` removes the node_modules folder before running it’s
+      # important to skip this step if cache was restored.
+      # `npm ci` does two things:
+      # 1. Installs everything in package-lock.json.
+      # 2. Checks that package.json and package-lock.json are in sync.
+      # That’s why the cache depends on both package-lock.json and package.json.
+      - name: npm ci
+        if: steps.cache-node_modules.outputs.cache-hit != 'true'
+        env:
+          # If you have a `"postinstall": "elm-tooling install"` script in your
+          # package.json, this turns it into a no-op. We’ll run it in the next
+          # step because of the caching. If elm-tooling.json changes but
+          # package-lock.json does not, the postinstall script needs running
+          # but this step won’t.
+          NO_ELM_TOOLING_INSTALL: 1
+        run: npm ci
+      
+      # Install tools from elm-tooling.json, unless we restored them from
+      # cache. package-lock.json and elm-tooling.json can change independently,
+      # so we need to install separately based on what was restored from cache.
+      # This is run even if we restored ~/.elm from cache to be 100% sure
+      # node_modules/.bin/ contains links to all your tools. `elm-tooling
+      # install` runs very fast when there’s nothing new to download so
+      # skipping the step doesn’t save much time.
+      - name: elm-tooling install
+        run: npx --no-install elm-tooling install
+      
+      # Finally, run whatever you want.
+
+      - name: elm-verify-examples
+        run: npx elm-verify-examples
+        
+      - name: elm-test
+        run: npx --no-install elm-test-rs