Bug fix hparam logging with metrics (#1647)

* add metric logging

* Use pytorch built-in method

* Update tensorboard.py

* Update tensorboard.py

pytorch_lightning/loggers/tensorboard.py

@@ -115,6 +115,7 @@ class TensorBoardLogger(LightningLoggerBase):
             )
         else:
             from torch.utils.tensorboard.summary import hparams
+
             if metrics is None:
                 metrics = {}
             exp, ssi, sei = hparams(sanitized_params, metrics)
@@ -123,6 +124,10 @@ class TensorBoardLogger(LightningLoggerBase):
             writer.add_summary(ssi)
             writer.add_summary(sei)
 
+            if metrics:
+                # necessary for hparam comparison with metrics
+                self.log_metrics(metrics)
+
         # some alternative should be added
         self.tags.update(sanitized_params)