Explain how to setup language in docker README
From https://discuss.tryton.org/t/improving-the-first-contact-with-tryton/768?u=ced, I found that we should explain how to define the main language at database initialization.
From https://discuss.tryton.org/t/improving-the-first-contact-with-tryton/768?u=ced, I found that we should explain how to define the main language at database initialization.