Register / return to the platform related issues

[luiz504]

1. When the user reserves a username, at the first step of the form, if he leaves the app and comes back from the home page, he can't continue the process.

• Validate at the Home page if the username exists and there's the cookie with its user-id, move the user to the next step valid.

2. When the account registration is completed there is no way to come to the schedule page, from the home page or any validation on the registration form process;

• If the username exists and there are no login cookies, create a step to log in via Google OAuth directly and set out a session cookie after that
• If there is some valid auth cookie redirect him to the schedule page