ignore bundle build outputs

Author: gmanchon

.github/workflows/build.yml

@@ -4,13 +4,13 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
-      - name: Install dependencies
-        run: bundle install
       - name: Build
         run: |
           git config user.name github-actions

.gitignore

@@ -1,2 +1,4 @@
 .DS_Store
 .ipynb_ckeckpoints
+.bundle/
+vendor/