title: Make buttons in a row have the same width in flutter
body: <p>If I want to make two or more <code>Buttons</code> in a <code>Row</code> to have the same <code>Width</code>, how do I make it?
  For examples I have three <code>RaisedButtons</code> with different title let say <code>Approve</code>, <code>Reject</code> and <code>Need Revise</code> and if I put the three <code>Button</code>s in a <code>Row</code>, they will have different <code>Width</code> and I don't want it. 
  What I need is for they have the same <code>Width</code>.</p>