Update User table to handle more info

Add following fields to User table in Postgres db, all fields are nullable

| Field      | Type | Constraint |
| ----------- | ----------- | ----------- |
| first_name      | Text       | |
| last_name   | Text        | |
| username   | Text        | unique |
| pfp   | Text        | |
| email   | Text        | |
| phone_number   | Text        | |

