Prices - Githubissues

In this PR I introduce the following changes:

[x] Added a price-per-day column to the Workspaces table
[x] Added a reservation_cost column to the Reservations table
[x] Added server-side calculation for the reservation_cost in the #create action of the Reservation controller
[x] Updated all relevant specs to account for the new columns as well as the new action in the Reservation controller
[x] Updates the Swagger-UI api-docs to reflect the new functionalities in the Workspace and Reservation endpoints
[x] Updated README.md with important information for anyone looking to make use of this repository in the future

badger-99 / workspace-reservation-back-end