Actions: add gems caching

.github/workflows/test.yml

@@ -30,15 +30,13 @@ jobs:
       - name: Disable gem docs
         run: 'echo "gem: --no-document" > ~/.gemrc'
 
-      - name: Set up Bundler
-        run: gem install bundler -v "~> 1.17"
-
-      - run: ruby --version
-      - run: gem --version
-      - run: bundle --version
-      - run: node --version
-      - run: npm --version
-      - run: java -version
+      - name: Set up Ruby cache
+        uses: actions/cache@v1
+        with:
+          path: vendor/bundle
+          key: ${{ runner.os }}-gem-${{ hashFiles('Gemfile') }}-${{ hashFiles('Gemfile.lock') }}-${{ hashFiles('.github/workflows/test.yml') }}
+          restore-keys: |
+            ${{ runner.os }}-gem-
 
       - name: Set up npm cache
         uses: actions/cache@v1
@@ -50,6 +48,16 @@ jobs:
             ${{ runner.OS }}-node-v{{ matrix.node }}-
             ${{ runner.OS }}-
 
+      - name: Set up Bundler
+        run: gem install bundler -v "~> 1.17"
+
+      - run: ruby --version
+      - run: gem --version
+      - run: bundle --version
+      - run: node --version
+      - run: npm --version
+      - run: java -version
+
       - name: Install npm dependencies
         run: npm install