Add tubist command

docs/utility/donkey.md

@@ -123,7 +123,7 @@ donkey makemovie --tub=<tub_path> [--out=<tub_movie.mp4>] [--config=<config.py>]
 
 ## Plot Predictions
 
-This command allows you plot steering and throttle against predictions coming from a trained model.
+This command allows you to plot steering and throttle against predictions coming from a trained model.
 
 Usage:
 
@@ -138,6 +138,24 @@ donkey tubplot --tub=<tub_path> --model=<model_path> [--limit=<end_index>] [--ty
 * Optional `--type=<model_type>` will use a different model type than the `DEFAULT_MODEL_TYPE`
 
 
+## Tub Histogram
+
+**_Note_**: Requires version >= 4.3
+
+This command allows you to plot tub data (usually steering and throttle) as a histogram.
+
+Usage:
+
+```bash
+donkey tubhist --tub=<tub_path> --record=<record_name> --out=<output_filename>
+```
+
+* This command may be run from `~/mycar` dir
+* Run on the host computer
+* Will show a pop-up window showing the histogram plot of tub values in a given tub
+* Optional `--record=<record_name>` will only show the histogram of a certain data series, for example "user/throttle"
+* Optional `--out=<output_filename>` saves histogram under that name, otherwise the name is auto-generated from the tub path
+
 ## Continuous Rsync
 
 This command uses rsync to copy files from your pi to your host. It does so in a loop, continuously copying files. By default, it will also delete any files