Add Discord event announcement functionality to backend

This commit introduces a new Discord event announcer to the backend, allowing for event announcements via Discord. It includes the addition of new environment variables for Discord configuration in `.env.example` and `compose.yaml`. The `main.go` file has been updated to initialize the announcer, and a new `discord` package has been created, containing the announcer logic and tests. Additionally, the service layer has been modified to support bracket draft management, enhancing the overall event workflow. Integration tests have been updated to ensure proper functionality of the new features.

backend/internal/application/service.go

@@ -30,6 +30,9 @@ type Store interface {
 	SaveRoster(context.Context, domain.RosterDraft, int) (domain.RosterDraft, error)
 	GetRoster(context.Context, string) (domain.RosterDraft, error)
 	ResetRoster(context.Context, string) error
+	SaveBracketDraft(context.Context, domain.BracketDraft, int) (domain.BracketDraft, error)
+	GetBracketDraft(context.Context, string) (domain.BracketDraft, error)
+	DeleteBracketDraft(context.Context, string) error
 	StartScrim(context.Context, domain.Event, int, []domain.Series, *domain.Tournament) error
 	DeleteEvent(context.Context, string) error
 	UpsertRSVP(context.Context, domain.RSVP) (domain.RSVP, error)
@@ -55,14 +58,26 @@ type Store interface {
 
 type Publisher interface{ Publish(topic string, value any) }
 
-type Service struct {
-	Store Store
-	Bus   Publisher
-	Now   func() time.Time
+type EventAnnouncer interface {
+	AnnounceEventCreated(context.Context, domain.Event) error
 }
 
-func New(store Store, bus Publisher) *Service {
-	return &Service{Store: store, Bus: bus, Now: func() time.Time { return time.Now().UTC() }}
+type Service struct {
+	Store               Store
+	Bus                 Publisher
+	EventAnnouncer      EventAnnouncer
+	AnnouncementTimeout time.Duration
+	Now                 func() time.Time
+}
+
+func New(store Store, bus Publisher, eventAnnouncer EventAnnouncer) *Service {
+	return &Service{
+		Store:               store,
+		Bus:                 bus,
+		EventAnnouncer:      eventAnnouncer,
+		AnnouncementTimeout: 3 * time.Second,
+		Now:                 func() time.Time { return time.Now().UTC() },
+	}
 }
 
 func NewID() string {
@@ -160,6 +175,11 @@ func (s *Service) CreateEvent(ctx context.Context, actor domain.Account, event d
 	out, err := s.Store.CreateEvent(ctx, event)
 	if err == nil {
 		s.Bus.Publish("events", out)
+		if s.EventAnnouncer != nil {
+			announcementCtx, cancel := context.WithTimeout(ctx, s.AnnouncementTimeout)
+			_ = s.EventAnnouncer.AnnounceEventCreated(announcementCtx, out)
+			cancel()
+		}
 	}
 	return out, err
 }