feat: propper db persistence w/ docker support

Dockerfile

@@ -1,6 +1,13 @@
 # --- Stage 1: Build the JAR ---
 FROM gradle:9.2.1-jdk21 AS build
 
+ARG DB_URL
+ARG DB_USERNAME
+ARG DB_PASSWORD
+ENV DB_URL=${DB_URL}
+ENV DB_USERNAME=${DB_USERNAME}
+ENV DB_PASSWORD=${DB_PASSWORD}
+
 # Set working dir
 WORKDIR /app
 
@@ -12,18 +19,20 @@ COPY --chown=gradle:gradle gradle ./gradle
 COPY --chown=gradle:gradle src ./src
 
 # Build the fat jar
-RUN ./gradlew clean shadowJar --no-daemon
+RUN ./gradlew clean build --no-daemon
 
 # --- Stage 2: Run the app ---
 FROM eclipse-temurin:21-jdk-alpine
 
+ARG PORT=9000
+
 WORKDIR /app
 
 # Copy the built JAR from the build stage
 COPY --from=build /app/build/libs/*.jar app.jar
 
 # Expose port (same as your server)
-EXPOSE 9000
+EXPOSE ${PORT}
 
 # Run the app
 ENTRYPOINT ["java", "-jar", "app.jar"]