tellstick: No such file or directory: 'socat': 'socat'

[theseal]

Home Assistant release with the issue:
0.93.2

Last working Home Assistant release (if known):
-

Operating environment (Hass.io/Docker/Windows/etc.):
Docker

Component/platform:
https://www.home-assistant.io/components/tellstick/

Description of problem:
The tellstick component requires socat to perform operations non-locally but socat isn't available in the Docker environment.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

tellstick:
  host: 192.168.2.96
  port: [50800, 50801]

Traceback (if applicable):

  2019-05-25 19:03:23 ERROR (MainThread) [homeassistant.setup] Error during setup of component tellstick                                      
Traceback (most recent call last):                                                                                                          
  File "/usr/src/app/homeassistant/setup.py", line 156, in _async_setup_component                                                           
    component.setup, hass, processed_config)  # type: ignore                                                                                
  File "/usr/local/lib/python3.7/concurrent/futures/thread.py", line 57, in run                                                             
    result = self.fn(*self.args, **self.kwargs)                                                                                             
  File "/usr/src/app/homeassistant/components/tellstick/__init__.py", line 75, in setup                                                     
    net_client.start()                                                                                                                      
  File "/usr/local/lib/python3.7/site-packages/tellcorenet.py", line 39, in start                                                           
    stdout=subprocess.DEVNULL                                                                                                               
  File "/usr/local/lib/python3.7/subprocess.py", line 775, in __init__                                                                      
    restore_signals, start_new_session)                                                                                                     
  File "/usr/local/lib/python3.7/subprocess.py", line 1522, in _execute_child                                                               
    raise child_exception_type(errno_num, err_msg, err_filename)                                                                            
FileNotFoundError: [Errno 2] No such file or directory: 'socat': 'socat'  

Additional information:
Everything works fine if you manually install socat.