feat(API): user invitations and emails

internal/infrastructure/persistence/models/inviteModel.go

@@ -0,0 +1,13 @@
+package models
+
+import "time"
+
+type Invite struct {
+	ID         uint32 `gorm:"primaryKey;autoIncrement"`
+	Email      string `gorm:"index;not null"`
+	HashedCode string `gorm:"not null"`
+	ExpiresAt  time.Time
+	InvitedBy  uint32 `gorm:"not null"`
+	AcceptedAt *time.Time
+	CreatedAt  time.Time `gorm:"autoCreateTime"`
+}