title: Sequence diagram with user interaction
body: <p>I am trying to draw a sequence diagram that requires user interaction. I tried to look for example online but I can't find it can anyone point me to the right direction?</p>
  
  <p>I would like to draw a sequence on the ios application where I click a button that trigger the camera and wait for user to take the photo. Next this photo will be save to my database. My difficulty is how can I draw a sequence flow which ask for user input? Is there a controller that I need to add into my sequence diagram e.g iosManager for triggering the camera? </p>