title: ImportError: cannot import name 'SummaryWriter'
body: <p>Can anyone help me on this error, I am trying to use allennlp models and getting the below error.</p>
  
  <pre><code> from allennlp.training.metrics import Average, BooleanAccuracy, 
   CategoricalAccuracy
   File "/home/administrator/aman/venv-kbs/lib/python3.6/site- 
   packages/allennlp/training/__init__.py", line 3, in &lt;module&gt;
   from allennlp.training.trainer import Trainer
   File "/home/administrator/aman/venv-kbs/lib/python3.6/site- 
   packages/allennlp/training/trainer.py", line 21, in &lt;module&gt;
   from tensorboard import SummaryWriter
   ImportError: cannot import name 'SummaryWriter'
  </code></pre>
  
  <p>Please find below the packages installed with the versions. </p>
  
  <pre><code>tensorboard             1.0.0a6
  tensorboard-pytorch     0.7.1
  tensorboardX            0.8
  tensorflow              1.4.0
  tensorflow-tensorboard  0.4.0
  </code></pre>