title: VSCode Remote Container - extensions not installing on dev container using docker-compose
body: <p>I am having trouble getting extensions installed in the dev container using "Remote - Containers". I do not know if it's a bug, incorrect configuration on my end, or intended behaviour. Down below is my current configuration, both files are located in the root folder of the project.</p>
  
  <p>docker-compose.yml</p>
  
  <pre><code>version: "3.7"
  
  services:
    api:
      image: node:12
      restart: always
      ports:
        - ${API_PORT}:3000
      volumes:
        - .:/usr/app
        - /usr/app/node_modules
      working_dir: /usr/app
      command: bash -c "yarn &amp;&amp; yarn dev"
  </code></pre>
  
  <p>.devcontainer.json</p>
  
  <pre class="lang-json prettyprint-override"><code>{
      "dockerComposeFile": "docker-compose.yml",
      "service": "api",
      "workspaceFolder": "/usr/app",
      "extensions": [
          "eamodio.gitlens",
          "formulahendry.auto-rename-tag",
          "coenraads.bracket-pair-colorizer-2",
          "kumar-harsh.graphql-for-vscode",
          "esbenp.prettier-vscode",
          "ms-vscode.vscode-typescript-tslint-plugin",
          "visualstudioexptteam.vscodeintellicode"
      ]
  }
  </code></pre>
  
  <p>The list of extensions listed in the <code>.devontainer.json</code> are the ones I want to have installed in the dev container. Any help is appreciated!</p>