working album navigation and duplicate checks on backend

backend/internal/models/album.go

@@ -14,8 +14,8 @@ type Album struct {
 	Private     bool           `gorm:"not null"`
 	// Public albums have a default access level of 0 for all visitors, including guests.
 	// Private albums require a user with access to be logged in to view, or a magic link to be used.
-	ParentID  string `gorm:"not null"` // The ID of the parent album, if any. This is an empty string for root albums.
-	Thumbnail string `gorm:"not null"` // The media ID of the thumbnail for the album.
+	ParentID  string `gorm:"not null"`            // The ID of the parent album, if any. This is an empty string for root albums.
+	Thumbnail string `gorm:"not null;default:''"` // The media ID of the thumbnail for the album.
 	CreatedAt time.Time
 	UpdatedAt time.Time
 }

backend/internal/models/user.go

@@ -4,7 +4,7 @@ import "time"
 
 type User struct {
 	ID        string `gorm:"primaryKey"`
-	Username  string `gorm:"not null"`
+	Username  string `gorm:"not null unique"`
 	Password  string `gorm:"not null"`
 	IsAdmin   bool   `gorm:"not null"`
 	IsRoot    bool   `gorm:"not null"`