Add Rating Field to Users

[IgorPolyakov]

Implement a new field rating in the users table to store. This score will be an integer in the database but should be displayed like 100.01 value with a fractional part.

Steps

1. Add a new field rating to the users table with the type int.
2. Implement a function to display the rating as a monetary value with two decimal places.
3. The calculation formula for the rating will be provided later - @sea-kg

Database Migration

ALTER TABLE users
ADD COLUMN rating INT DEFAULT 0;