Sets up environment variables within the docker-compose file,
replacing the use of a .env file. This includes defining
variables for Django secret key, allowed hosts, SMTP settings,
and sender name. This change improves configuration management
and clarifies the necessary environment settings.
Implements a mechanism to automatically clear overlapping events in user calendars.
Introduces a new model for email templates, enabling customizable notifications to event organizers when their events are declined due to overlaps.
Adds a background task to find overlapping events based on calendar settings and automatically cancels the later event, sending a notification email to the organizer, if configured.