Implemented the changes required to successfully execute the unit tests.

config/database.php
    Inserted the local database credentials in the config file for getting connected to the database.
    Updated the getPort method defination.
core/database.php
    Updated the the link of the database connection in the constructor.
core/logging.php
    Updated the class defination syntax of the declared Logging class.
models/question.php
    Reframed the select query in the constructor and getAnswerById method of the class.
    Updated the syntax of fetching data from the received array in constructor for "created" parameter.
    Updated the syntax of the array declared in the addQuestion method.
boot.php
    Removed the comments applied for the required files.
README.md
    Inserted the output for the test cases in the file.
schema.sql
    Inserted the updated statements for the database.