Creating A New Application

Week 1: Your First Rails Application · Lesson 1 ·

I'm going to show you how to create a new Ruby on Rails application

Create a new Ruby on Rails app

In your command line, type:

$ cd ~/Desktop # Makes sure you're on your desktop to begin with
$ pwd # Just to make sure
$ rails new omruby
... # A new Rails app is created

The Ruby on Rails App Structure

A typical Ruby on Rails app is structured like this:

app/ Where most of your code will go

bin/ Where special Rails commands go. Don't worry about this.

config/ This is where configuration and customization files go. Another configuration file.

db/ Where your database lives.

Gemfile Where other people's libraries of code gets installed from.

Gemfile.lock Generated automatically from the Gemfile.

lib/ Here's where you can store code you want to share between applications.

log/ Where log files go.

public/ Where public files and images go.

Rakefile Special tasks you can create for your Rails application. Later we'll put text here that tells people about this app.

test/ Where automated tests go.

tmp/ Stores temporary files.

vendor/ Where other people's files goes that you've downloaded.

Running the Server

In your command line type:

$ cd omruby # Make sure you're in the newly created folder
$ rails server
=> Booting Puma
=> Rails application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
Puma starting in single mode...
Use Ctrl-C to stop

Then visit http://localhost:3000 in your browser.

Yay! You ran your first Rails app.

Common Issues

You get a "This site can’t be reached" error. Did your Rails server start properly? Check your command line to see if you got a warning message.

The command `rails server` doesn't work. Are you sure you used `cd` to change directory into your new folder? You can only run the rails server from inside your Rails application folder.