Enhancement description

I have these errors in log on each start:

backend_1   | Initializing database
backend_1   | Operations to perform:
backend_1   |   Apply all migrations: admin, api, auth, authtoken, contenttypes, sessions, social_django
backend_1   | Running migrations:
backend_1   |   No migrations to apply.
backend_1   |   Your models have changes that are not y

Create text classification project that shows text to the annotator. The text also includes URLs or terms that the annotator may want to look up.
However normal copying the string to look up is not possible, presumably because the code that normally handles text selection in order create a sequence annotation (like for NER) is active.
"Normal copying" would be that the user marks the text to

In order to make contribution more clear I suggest a similar aproach:

https://github.com/facebook/draft-js/blob/a9316a723f9e918afde44dea68b5f9f39b7d9b00/CONTRIBUTING.md

Also for more clear Issue templating I recommand : https://github.com/GRAAL-Research/poutyne/tree/master/.github/ISSUE_TEMPLATE

I wanted to propose a PR but some point where not clear (linter, yapf).

Users find it hard to understand what the three panels in the bottom bar are for. Use tooltips or labels or design it in a different way somehow.

@omm test string @omm results in @omm@omm test string @omm after expand

"mention": func(b string) string {
				// Take substring from index 4 to length of string.
				return fmt.Sprintf(`<a href="/test/%[1]s">%[1]s</a>`, b)
			},

If, in docker-compose.yml we set DEBUG=True, we end up with an error 500.