diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..8c9ff1e
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,26 @@
+# syntax=docker/dockerfile:1
+
+FROM php:8.2-apache
+
+WORKDIR /var/www/html
+
+# Install Composer by copying its binary from the official composer image
+COPY --from=composer:lts /usr/bin/composer /usr/bin/composer
+
+# Copy dependency manifests first so Docker can cache this layer
+# (only re-runs composer install if these files change)
+COPY composer.json composer.lock ./
+
+# Install PHP dependencies (production only, no dev packages)
+RUN composer install --no-dev --no-interaction --optimize-autoloader
+
+# Use production php.ini defaults
+RUN mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
+
+# Copy the rest of the application source
+COPY ./src /var/www/html
+
+# Make sure the web server user owns the files
+RUN chown -R www-data:www-data /var/www/html
+
+USER www-data
diff --git a/README.md b/README.md
index 83d84f8..5d045e8 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,104 @@
-# docker-php-sample
+# Docker PHP Sample
 
-A simple PHP web application example for [Docker's PHP Language Guide](https://docs.docker.com/language/php/).
\ No newline at end of file
+A simple PHP application containerized with Docker, using the official
+`php:8.2-apache` image. Dependencies are managed with Composer.
+
+## Project structure
+
+```
+docker-php-sample/
+├── Dockerfile        # Single-stage build: PHP 8.2 + Apache + Composer deps
+├── composer.json      # PHP dependency manifest
+├── composer.lock       # Locked dependency versions
+├── src/               # Application source code (web root)
+├── tests/             # Test suite
+└── README.md
+```
+
+## Prerequisites
+
+- [Docker](https://docs.docker.com/get-docker/) installed and running
+- Your user added to the `docker` group (or use `sudo` for Docker commands)
+  ```bash
+  sudo usermod -aG docker $USER
+  newgrp docker
+  ```
+
+## Build the image
+
+From the project root:
+
+```bash
+docker build -t php-app:latest .
+```
+
+This will:
+1. Start from the `php:8.2-apache` base image
+2. Copy the Composer binary in from the official `composer` image
+3. Install PHP dependencies via `composer install`
+4. Switch to production `php.ini` defaults
+5. Copy in the application source from `src/`
+6. Run the container as the non-root `www-data` user
+
+## Run the container
+
+```bash
+docker run -d -p 9000:80 php-app:latest
+```
+
+- `-d` runs the container in the background (detached)
+- `-p 9000:80` maps port `9000` on your host to port `80` inside the container
+
+Check it's running:
+
+```bash
+docker ps
+```
+
+You should see something like:
+
+```
+PORTS
+0.0.0.0:9000->80/tcp
+```
+
+## Access the app
+
+Open in your browser:
+
+```
+http://localhost:9000/hello.php
+```
+
+Or, if running on a remote server (e.g. EC2), replace `localhost` with the
+server's public IP, and make sure port `9000` is allowed in your firewall /
+security group inbound rules.
+
+## Stopping the container
+
+```bash
+docker ps                # find the container ID or name
+docker stop <container>  # stop it
+docker rm <container>    # remove it (optional)
+```
+
+## Rebuilding after code changes
+
+Any time you change `src/`, `composer.json`, or the `Dockerfile` itself,
+rebuild the image and restart the container:
+
+```bash
+docker build -t php-app:latest .
+docker stop <container> && docker rm <container>
+docker run -d -p 9000:80 php-app:latest
+```
+
+## Notes
+
+- This Dockerfile is **single-stage** (no multi-stage build), so the final
+  image includes Composer and its cache — larger than a multi-stage build,
+  but simpler to read and doesn't require BuildKit.
+- If you see `the --mount option requires BuildKit`, that means a
+  Dockerfile is using BuildKit-only syntax (`RUN --mount=...`). Either
+  enable BuildKit (`DOCKER_BUILDKIT=1 docker build ...`) or use the
+  single-stage Dockerfile in this repo, which avoids that syntax entirely.
diff --git a/src/database.php b/src/database.php
deleted file mode 100644
index 88a2692..0000000
--- a/src/database.php
+++ /dev/null
@@ -1,47 +0,0 @@
-<?php
-
-// Read the database connection parameters from environment variables
-$db_host = getenv('DB_HOST');
-$db_name = getenv('DB_NAME');
-$db_user = getenv('DB_USER');
-
-// Read the password file path from an environment variable
-$password_file_path = getenv('PASSWORD_FILE_PATH');
-
-// Read the password from the file
-$db_pass = trim(file_get_contents($password_file_path));
-
-// Create a new PDO instance
-$db_handle = new PDO("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);
-
-// Create the "messages" table if it doesn't exist
-$db_handle->exec("
- CREATE TABLE IF NOT EXISTS messages (
-     id INT AUTO_INCREMENT PRIMARY KEY,
-     message VARCHAR(255) NOT NULL
- )
-");
-
-// Create message
-$stmt = $db_handle->query("SELECT COUNT(*) as count FROM messages");
-$row = $stmt->fetch(PDO::FETCH_ASSOC);
-$count = $row['count'];
-$db_handle->exec("
- INSERT INTO messages (message)
- SELECT CONCAT('message-', '$count')
- WHERE NOT EXISTS (
-  SELECT 1 FROM messages WHERE message = CONCAT('message-', '$count')
- )
-");
-
-// Retrieve all records from the "messages" table
-$stmt = $db_handle->query("SELECT * FROM messages");
-
-// Print all records
-while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
- echo $row['id'] . " " . $row['message'] . "<br>";
-}
-
-// Close the database connection
-$db_handle = null;
-?>