title: rubocop on VScode not working.Error "rubocop is not executable"
body: <p>Recently I installed rubocop on vscode. However, it doesn't work.Error message is below.</p>
  
  <pre><code>rubocop is not excutable 
  execute path is empty! please check ruby.rubocop.executePath
  </code></pre>
  
  <p>How should I fix it? I searched some articles, never solved...</p>
  
  <p>cf. vscode-ruby-rubocop
  <a href="https://github.com/misogi/vscode-ruby-rubocop" rel="noreferrer">https://github.com/misogi/vscode-ruby-rubocop</a></p>