User Story #21: As an Admin I want to sign in to the web application so I can manage the users’ profiles and their payments.
Acceptance criteria:
Given I have admin account in the app And I'm on the login page
When I entered email address and password And it's correct
Then the system should log me in And navigate me to homepage
Admin account will be created in the database.
Errors processing:
If credentials are not correct - the message should be shown 
