[x] When logged out, I should see a "Sign up" button next to the "Log in" button (or drop down menu containing a "Sign up" menu option below a "Log in" menu option) in the top-right corner of the header on every page of the site.
[x] Upon clicking "Sign up" to open the sign-up modal pop-up window, a new user account form.
[x] The new user account form should show placeholders or labels and input boxes for: "First Name", "Last Name", "Email", "Username", "Password", and "Confirm Password".
[x] The new user account form should show a "Sign up" button after all the input boxes.
[x] The "Sign up" button should be disabled when any field is empty.
[x] The "Sign up" button should be disabled when the "Username" field is less than 4 characters.
[x] The "Sign up" button should be disabled when the "Password" field is less than 6 characters.
[x] The "Sign up" button should be disabled when the field for "Confirm Password" does not match the field for "Password".
[x] When clicking "Sign up" button on the new user account form with errors in the form, it must show all error messages returned from the backend (similar to the following): "The provided email is invalid" or "Username must be unique".
[x] Upon closing and reopening sign-up modal, the errors are reset (all errors displayed before closing the modal are gone).
[x] Upon closing and reopening sign-up modal, all fields are empty (all data entered before has been cleared).
[x] Upon closing and reopening sign-up modal, the "Sign up" button on the new user account form is disabled.
[x] After a successful sign-up is completed, the new user should automatically be logged in and see the User Menu with their information entered during sign-up with a "Log out" menu option, but not "Log in" or "Sign up" menu options.
[x] After a successful sign-up is completed, if the new user refreshes the browser, they should still see the User Menu Button with the new user's information in the user drop down menu.