Add PerformanceReview feature

[amaurymedeiros]

Add a reviews field to User model. A list of PerformanceReview

PerformanceReview model should contain the following fields:

• author (required) - The user who asks for a performance review
• admins (required) - A list of ADMIN users that can reply to the review
• description (required) - The user's explanation regarding why their performance should be reviewed

PerformanceReview controller should include the following methods:

• create (Regular users only)
• update (Only the user that created the review)
• delete (Only the user that created the review)
• list (ADMIN can only list reviews which he belongs to the admins list. Regular users can only list reviews created by themselves)
• show (ADMIN can only view reviews which he belongs to the admins list. Regular users can only view reviews created by themselves)
• reply (ADMIN can only reply to reviews which he belongs to the admins list. Regular users can only reply to reviews created by themselves)

Suggested tests:

• Create review using an ADMIN user (should return 401 - Unauthorized)
• Create review using a user from any other level (should return 201 - Created)
• Update review using the user that created it (should return 200 - OK)
• Update review using a user that hasn't created it (should return 401 - Unauthorized)
• Delete review using the user that created it (should return 200 - OK)
• Delete review using a user that hasn't created it (should return 401 - Unauthorized)
• List all reviews using an ADMIN user (should return 200 - OK, displaying only the reviews that has this ADMIN on the admins list)
• List all reviews using a user from any other level (should return 200 - OK, displaying only the reviews created by them)
• View a review using the user that created it (should return 200 - OK)
• View a review using a regular user that hasn't created it (should return 401 - Unauthorized)
• View a review using an ADMIN user that is not on the admins list of the review (should return 401 - Unauthorized)
• View a review using an ADMIN user that is on the admins list of the review (should return 200 - OK)
• Create/Update review without required fields