Implement ability to log in as a patient

[neraks]

As a Patient, I want to be able to log in securely to see my Patient Dashboard.

Acceptance criteria 1:
Given I am a registered patient
When I go to the homepage
Then I can see a link to log in as a Patient that takes me to the login page.

Acceptance criteria 2:
Given I am a registered patient
When I go to the login page
Then I see two labeled input fields and a submit button:

• Username (no max length)
• Password (no max length)

Acceptance criteria 3:
Given I am a registered user
When I submit my username and password on the login page
Then I am taken to a dashboard page that can only be accessed by me when I am logged in.