Adding heroku support to the project

We will be using heroku to deploy the project
Configuring database and jdk settings for heroku
Changing the table name of User domain class to author.

This was done to prevent conflict with heroku postgresql database
Converting tabls to spaces
Disabling database migration runtime plugin
Removing User model class and unit test.

We’ll use the domain class generated by spring security plugin
Implemting user login and logout functionality

When no users are present we are creating a user with email
admin@example.com and password 123456

When no roles are present we are creating two roles ROLE_AUTHOR and
ROLE_ADMIN