title: How to align Column's children in different positions in Flutter?
body: <p>How to achieve the following design in Flutter?</p>
  
  <p>I'm trying to position a Card and a Button within a Column.</p>
  
  <p>The Card must be positioned centered in the Column wihtout taking into consideration the height of the Button.</p>
  
  <p>And the Button must be positioned at the bottom of the Column.</p>
  
  <p><a href="https://i.stack.imgur.com/bBpl2.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bBpl2.png" alt="Design"></a></p>