fix #7: use Docker service name backend:8000 instead of localhost in Dockerfile ENV

Author: DHANUSHGCODE

frontend/Dockerfile

@@ -18,7 +18,9 @@ COPY . .
 
 # Environment variables for build
 ENV NEXT_TELEMETRY_DISABLED 1
-ENV NEXT_PUBLIC_API_URL=http://localhost:8000
+# Fix #7: Use Docker service name 'backend' instead of localhost
+# 'localhost' does not resolve to the backend container at build time
+ENV NEXT_PUBLIC_API_URL=http://backend:8000
 
 # Build the application
 RUN npm run build
@@ -30,27 +32,17 @@ WORKDIR /app
 ENV NODE_ENV production
 ENV NEXT_TELEMETRY_DISABLED 1
 
-# Create a non-root user
+# Create non-root user for security
 RUN addgroup --system --gid 1001 nodejs
 RUN adduser --system --uid 1001 nextjs
 
-# Copy built application
 COPY --from=builder /app/public ./public
 COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
 COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
 
-# Switch to non-root user
 USER nextjs
 
-# Expose port
 EXPOSE 3000
-
 ENV PORT 3000
-ENV HOSTNAME "0.0.0.0"
-
-# Health check
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
-    CMD node -e "require('http').get('http://localhost:3000', (r) => {process.exit(r.statusCode === 200 ? 0 : 1)})"
 
-# Run the application
 CMD ["node", "server.js"]