title: Whats is the use of annotation group in doctrine
body: <p>I am new to doctrine, In my symfony project all the entity annotation linked with groups but <strong>I am not getting what is the use of Groups.</strong></p>
  
  <pre><code>/**
       * @ORM\Column(type="string", length=64)
       * @Groups({"public","details"})
       */
  </code></pre>
  
  <p>I have newly added the field in my entity file, while executing the schema update getting (newly added field) was never imported.</p>
  
  <p>What is groups and how it's useful.</p>