Rails installation and setup - Mini Project: Build & Apply

Rails installation and setup

📖 Scenario: You want to start a new web project using Ruby on Rails. First, you need to install Rails and create a new Rails application on your computer.

🎯 Goal: Set up Ruby on Rails by installing the Rails gem and creating a new Rails application named myapp.

📋 What You'll Learn

Install the Rails gem version 7.0.0 or higher

Create a new Rails application named myapp

Navigate into the myapp directory

Start the Rails server to verify the setup

💡 Why This Matters

🌍 Real World

Setting up Rails is the first step to building web applications with Ruby on Rails, a popular framework for websites and APIs.

💼 Career

Knowing how to install and start a Rails project is essential for Ruby on Rails developers and web engineers working with this framework.

1

Install Rails gem

Run the command gem install rails -v 7.0.0 in your terminal to install Rails version 7.0.0.

Ruby on Rails

# Run gem install rails -v 7.0.0 in your terminal

Hint

Use the gem install command followed by rails -v 7.0.0 to install Rails version 7.0.0.

2

Create a new Rails application

Run the command rails new myapp in your terminal to create a new Rails application named myapp.

Ruby on Rails

gem install rails -v 7.0.0
# Run rails new myapp in your terminal

Hint

Use the rails new command followed by the app name myapp to create the project.

3

Navigate into the application directory

Run the command cd myapp in your terminal to move into the myapp directory.

Ruby on Rails

gem install rails -v 7.0.0
rails new myapp
# Run cd myapp in your terminal

Hint

Use the cd command to change directory into myapp.

4

Start the Rails server

Run the command bin/rails server in your terminal to start the Rails server and verify the setup.

Ruby on Rails

gem install rails -v 7.0.0
rails new myapp
cd myapp
# Run bin/rails server in your terminal

Hint

Use bin/rails server to start the Rails web server.

Practice

1. What is the main purpose of running gem install rails in your terminal?

easy

A. To install the Rails framework on your computer

B. To create a new Rails project

C. To start the Rails server

D. To update Ruby to the latest version

Solution

1. Step 1: Understand the command gem install rails

   This command uses Ruby's package manager (gem) to install the Rails framework on your system.

2. Step 2: Differentiate from other commands

   Creating a project uses rails new, and starting the server uses rails server. Updating Ruby is separate.

3. Final Answer:

   To install the Rails framework on your computer -> Option A

4. Quick Check:

   Install Rails = gem install rails [OK]

Hint: Install Rails with gem install rails command [OK]

Common Mistakes:

• Confusing installation with project creation
• Trying to start server before installing Rails
• Mixing Ruby update with Rails installation

2. Which command correctly creates a new Rails application named myapp?

easy

A. rails create myapp

B. rails new myapp

C. gem new myapp

D. rails start myapp

Solution

1. Step 1: Identify the correct Rails command for project creation

   The command to create a new Rails app is rails new appname.

2. Step 2: Check each option

   rails create myapp uses 'create' which is incorrect. gem new myapp uses 'gem' which manages packages, not projects. rails start myapp uses 'start' which is for running the server.

3. Final Answer:

   rails new myapp -> Option B

4. Quick Check:

   Create app = rails new [OK]

Hint: Use rails new appname to create a project [OK]

Common Mistakes:

• Using 'rails create' instead of 'rails new'
• Confusing gem commands with Rails commands
• Trying to start app with wrong command

3. After running rails new blog and then cd blog, what happens when you run rails server?

medium

A. Starts a web server accessible at http://localhost:3000

B. Creates a new Rails project named blog

C. Installs Rails gems needed for the project

D. Displays an error because the server command is invalid

Solution

1. Step 1: Understand the rails server command

   This command starts the Rails web server so you can view your app in a browser.

2. Step 2: Confirm the server address

   By default, the server runs on port 3000 and is accessible at http://localhost:3000.

3. Final Answer:

   Starts a web server accessible at http://localhost:3000 -> Option A

4. Quick Check:

   rails server = start web server [OK]

Hint: rails server runs app at localhost:3000 [OK]

Common Mistakes:

• Thinking rails server creates a project
• Expecting gem installation during server start
• Assuming server command is invalid

4. You ran rails new myapp but got an error saying 'command not found: rails'. What is the most likely cause?

medium

A. Ruby is not installed on your system

B. You forgot to create the project folder manually

C. Rails gem is not installed or not in your PATH

D. You need to run rails server first

Solution

1. Step 1: Analyze the error 'command not found: rails'

   This error means the system cannot find the rails command, usually because the Rails gem is missing or not accessible.

2. Step 2: Check other options

   Creating a folder manually is not needed; Ruby missing would cause a different error; running server first is unrelated.

3. Final Answer:

   Rails gem is not installed or not in your PATH -> Option C

4. Quick Check:

   Missing rails gem = command not found [OK]

Hint: Install Rails gem before using rails commands [OK]

Common Mistakes:

• Assuming folder must be created manually
• Confusing Ruby absence with Rails command error
• Trying to run server before project exists

5. You want to create a new Rails app but skip installing all default gems to speed up setup. Which command should you use?

hard

A. rails new appname --skip-install

B. rails new appname --no-gems

C. gem install rails --skip-defaults

D. rails new appname --skip-bundle

Solution

1. Step 1: Identify the option to skip gem installation during project creation

   The --skip-bundle flag tells Rails to create the app without running bundle install which installs gems.

2. Step 2: Evaluate other options

   rails new appname --no-gems is invalid syntax, gem install rails --skip-defaults misuses gem install, rails new appname --skip-install is not a recognized flag.

3. Final Answer:

   rails new appname --skip-bundle -> Option D

4. Quick Check:

   Skip gem install = --skip-bundle [OK]

Hint: Use --skip-bundle to skip gem install on new app [OK]

Common Mistakes:

• Using invalid flags like --no-gems or --skip-install
• Trying to skip gem install with gem install command
• Confusing bundle install with rails new options