fix: use DATABASE_FILE env var consistently and update Dockerfile

Dockerfile

@@ -42,8 +42,8 @@ RUN apt-get update && apt-get install -y ca-certificates sqlite3 && rm -rf /var/
 # Create data directory for sqlite
 RUN mkdir -p /app/data
 
-# Set DB_PATH to use the persistent volume
-ENV DB_PATH=/app/data/mal.db
+# Set DATABASE_FILE to use the persistent volume
+ENV DATABASE_FILE=/app/data/mal.db
 
 COPY --from=builder /app/main_server .
 COPY --from=builder /app/templates ./templates

internal/database/database.go

@@ -24,10 +24,7 @@ var Module = fx.Options(
 )
 
 func ProvideSQLDB() (*sql.DB, error) {
-	dbPath := os.Getenv("DB_PATH")
-	if dbPath == "" {
-		dbPath = "mal.db"
-	}
+	dbPath := db.GetDBFile()
 	dbConn, err := db.Open(dbPath)
 	if err != nil {
 		return nil, fmt.Errorf("failed to open database: %w", err)