Issue closes: #6

This PR contains

Authenticate the request and build the user context in the middleware.

Fetch the latest ticket_revision from the ticket_id
Validate the to_stage and assignee with the available process_path from current_stage
If validated successfully update the ticket table with closed status
Create a new entry in the ticket_activity table with current_stage as ticket_closed id from stage table
If validation fails, send proper error message

Please review : @uttahb

Please let me know for any changes or suggestions.