Update README.md
Do not allow empty ticket creation from the UI

Closes #50
Fine-tune styles
Add User#getUsername()
Do not allow config.js to be loaded in the browser
Add User#getOrganisationDomain()
Managers get all tickets listed on /api/tickets
fix test name
Retrofit tests for 666bdedbe8f83b28210523a70
Depend on nodemailer #18
Add tests for email sending from comments #18