title: Flask-admin and prepopulated value
body: <p>I have small issue: simple class</p>
  
  <pre><code>class AModel(db.Model):
    id = db.Column(....)
    title = db.Column(....)
    uniq_text_id = db.Column(db.String(50), unique=True. nullable=False)
  
  def __init__(self):
    uniq_text_id = uuid4().hex
  </code></pre>
  
  <p>Now i adjusted flask-admin package and what administrator be able to create <code>AModel</code> instances. But there is 1 case: field <code>uniq_text_id</code> must be created automatically.</p>
  
  <p>So, right now I cannot create mode because flask-admin says that fiel uniq_text_id in required, but also does not shows prepopulated value.</p>
  
  <p>Is there any way to use prepopulated value in flask-admin forms or avoid somehow this problem without dropping <code>nullable=False</code> constraint?</p>
  
  <p><strong>UPD:</strong> @codegeek provided good solution for auto generated fields which still shown on the form. My own solution uses provided by flask-admin functionality allows to explicitly declares which columns are shown and which - hidden.</p>