Feature suggestion: On-screen message alerting that login is required to access the view tab

[CarolusVitalis]

Since access to the View tab requires a login, if a study is accessed through its direct link, in the format http://flapjack.rudge-lab.org/view?study=x&assay=y&vector=z the screen remains in the home page. The creation of a message on the screen indicating that is required to login before proceeding to the View tab is necessary.

The proposal could follow the next workflow:

1. Someone enters an address in the http://flapjack.rudge-lab.org/view?study=x&assay=y&vector=z format without having previously logged in.
2. The browser is redirected to a page stating "To continue to the View tab you need to log in (go to 3). Don't have an account yet? Register here! (go to 4).
3. The user is redirected to the login, after logging in he/she is redirected to the View tab. To achieve this, a modifier could be added to the URL to indicate the server where you want to be redirected, it could follow the following format: http://flapjack.rudge-lab.org/authentication?view&study=x&assay=y&vector=z
4. The user is redirected to the sign-up tab, maybe a direct link could use the following format: http://flapjack.rudge-lab.org/authentication?signup

To reproduce the behavior:
Make sure you are not logged in to Flapjack and go to a study using its direct URL.