User can sign in

As a user, i want to be able to sign in in order to access the site.

_Acceptance Criteria_
GIVEN A user
WHEN a user goes to the sign in page
THEN user should see a form with the fields for email address and password input

_Developer Notes_
The user should be able to sign in with this form

_Design Notes_
The UI should be user friendly

Start by locating the sign-in page entry point and reviewing how existing pages handle forms and authentication. Implement the user-facing sign-in form with email address and password fields, then verify that a user can submit it and access the site.

Written by the indexing model from the issue text.