title: How to add learning rate to summaries?
body: <p>How do I monitor learning rate of AdamOptimizer?
  In <a href="https://www.tensorflow.org/versions/r0.11/how_tos/summaries_and_tensorboard/index.html" rel="nofollow noreferrer">TensorBoard: Visualizing Learning</a> is said that I need </p>
  
  <blockquote>
    <p>Collect these by attaching scalar_summary ops to the nodes that output the learning rate and loss respectively.</p>
  </blockquote>
  
  <p>How can I do this?</p>