502 Bad Gateway. After implementing the application on 'digitalocean'
502 probably means you got some errors in your application - you'd better check out your gunicorn(or other WSGI server) logs. Location of the logs depends on what WSGI server you're using but probably you can check it out in WSGI's config file.
Also you can try to do standard 'runserver' just to ensure that your application can run correctly. 
ps aux | grep gunicorn (or smth like this command) can tell you if it's runnning.
If it's not, chek out the logs. Also, you can go to your config file, check the command that you're trying to use to start the server, try it out in the console.
In final you can ensure that your nginx config is correct too with nginx -t command.
I added my applications on DigitalOcean. But when I turn on my website I see the error. "502 Bad Gateway nginx/1.14.0 (Ubuntu)". I would like to solve it, but I do not know where I can find logs with errors.
I always used CMD and when I tried to turn on the server, if something did not work, the CMD clearly said what was wrong. Where can I find something like this on DigitalOcean. I used PythonAnywhere once, and there was a separate tab with information about errors (practically the same as in CMS). Please forgive me for simple questions, I have little experience in servers and GIT.