title: How to change enum values in Mongoose
body: <p>I have a enum property in my mongoose collection that was initial defined as <code>const actions = ['a', 'b', 'c']</code> I have a requirement to change it to add addition actions <code>const actions = ['a', 'b', 'c', 'd', 'e']</code> to the enum but when I try to use the additional values i.e. <code>action = 'e'</code> I get a validation error <code>&quot;Model validation failed: action: 'e' is not a valid enum value for path 'action'.&quot;</code></p>
  <p>My question is how do I add additional values to the enum to a mongo collection in mongoose already in production.</p>
  <pre class="lang-js prettyprint-override"><code>mongoose.model('Model', new Schema({
    action: {
      type: String,
      required: true,
      enum: actions,
      immutable: true
    }}))
  </code></pre>