Changes to Dockerfile to fix error in installing MongoDB

docker/Dockerfile

@@ -16,8 +16,13 @@ COPY src/backend/ ./src/backend/
 # Stage 3: Final production image
 FROM node:18-alpine
 
-# Install nginx and MongoDB
-RUN apk add --no-cache nginx mongodb
+# Install nginx
+RUN apk add --no-cache nginx
+
+# Install MongoDB (from MongoDB's official repositories for Alpine)
+RUN echo "https://repo.mongodb.org/apk/alpine/v5.0/main" > /etc/apk/repositories \
+    && apk update \
+    && apk add --no-cache mongodb-org
 
 # Configure nginx
 COPY docker/nginx.conf /etc/nginx/nginx.conf
@@ -27,7 +32,7 @@ COPY --from=frontend-builder /app/dist /usr/share/nginx/html
 COPY --from=backend-builder /app/node_modules ./node_modules
 COPY --from=backend-builder /app/src/backend ./src/backend
 
-# Create necessary directories
+# Create necessary directories for nginx and MongoDB
 RUN mkdir -p /var/log/nginx && \
     mkdir -p /var/lib/nginx && \
     chown -R nginx:nginx /var/log/nginx /var/lib/nginx
@@ -37,8 +42,8 @@ ENV MONGO_DATA_DIR=/data/db
 RUN mkdir -p $MONGO_DATA_DIR && \
     chown -R mongodb:mongodb $MONGO_DATA_DIR
 
-# Expose necessary ports
-EXPOSE 8080 8081 8082 27017
+# Expose necessary ports (nginx on 8080, Node.js backend on 8081, MongoDB on 27017)
+EXPOSE 8080 8081 27017
 
 # Use an entrypoint script to run services (nginx, MongoDB, and Node backend)
 COPY docker/entrypoint.sh /entrypoint.sh