---
title: Use containers for Ruby on Rails development
linkTitle: Develop your app
weight: 40
keywords: ruby, local, development
description: Learn how to develop your Ruby on Rails application locally.
aliases:
  - /language/ruby/develop/
  - /guides/language/ruby/develop/
---

## Prerequisites

Complete [Containerize a Ruby on Rails application](containerize.md).

## Overview

In this section, you'll learn how to set up a development environment for your containerized application. This includes:

- Adding a local database and persisting data
- Configuring Compose to automatically update your running Compose services as you edit and save your code

## Add a local database and persist data

You can use containers to set up local services, like a database. In this section, you'll update the `compose.yaml` file to define a database service and a volume to persist data.

In the cloned repository's directory, open the `compose.yaml` file in an IDE or text editor. You need to add the database password file as an environment variable to the server service and specify the secret file to use.

The following is the updated `compose.yaml` file.

```yaml {hl_lines="07-25"}
services:
  web:
    build: .
    command: bundle exec rails s -b '0.0.0.0'
    ports:
      - "3000:3000"
    depends_on:
      - db
    environment:
      - RAILS_ENV=test
    env_file: "webapp.env"
  db:
    image: postgres:latest
    secrets:
      - db-password
    environment:
      - POSTGRES_PASSWORD_FILE=/run/secrets/db-password
    volumes:
      - postgres_data:/var/lib/postgresql/data

volumes:
  postgres_data:
secrets:
  db-password:
    file: db/password.txt
```

> [!NOTE]
>
> To learn more about the instructions in the Compose file, see [Compose file
> reference](/reference/compose-file/).

Before you run the application using Compose, notice that this Compose file specifies a `password.txt` file to hold the database's password. You must create this file as it's not included in the source repository.

In the cloned repository's directory, create a new directory named `db` and inside that directory create a file named `password.txt` that contains the password for the database. Using your favorite IDE or text editor, add the following contents to the `password.txt` file.

```text
mysecretpassword
```

Save and close the `password.txt` file. In addition, in the file `webapp.env` you can change the password to connect to the database.

You should now have the following contents in your `docker-ruby-on-rails`
directory.

```text
.
├── Dockerfile
├── Gemfile
├── Gemfile.lock
├── README.md
├── Rakefile
├── app/
├── bin/
├── compose.yaml
├── config/
├── config.ru
├── db/
│   ├── development.sqlite3
│   ├── migrate
│   ├── password.txt
│   ├── schema.rb
│   └── seeds.rb
├── lib/
├── log/
├── public/
├── storage/
├── test/
├── tmp/
└── vendor
```

Now, run the following `docker compose up` command to start your application.

```console
$ docker compose up --build