Lesson: generate a rails application

Goals

• Create your new Ruby on Rails Application
• Initialize the local git repository for your project

Explanation

Note: This lesson is roughly covers the Getting Started and Create A New Git Repo steps in the RailsBridge Curriculum.

This lesson assumes you are using a 5.0.x version of rails. To avoid confusion, it's better to have a clean gemset with only one version of rails installed. Most people use either RVM or rbenv to handle gemsets and ruby versions.

The first step to creating a Hydra Head, or any other type of Rails Application, is to generate the basic skeleton of the application code.

We'll also initialize our Git repository in this lesson so we can track incremental changes to our code. In order to track the changes you make to your code, to share your changes with others, and to pull other people's changes into your code, you need some form of Version Control. The Hydra community uses Git for version control and to share work on Github.

Steps

Step 1: Create a new rails application

Once you have installed a suitable rails gem (5.0.x releases work best for this tutorial), begin by using it to generate a new rails application. You can choose any name for your application. In this tutorial we are calling it hydra-works-demo

rails new hydra-works-demo

This generates the file structure for an empty rails application. And it runs 'bundler' which loads in all of the external dependencies for rails.

Enter the directory for the new rails app:

cd hydra-works-demo

When you type ls at the command prompt, you should see a file structure like this:

Gemfile		Rakefile	config.ru	lib		script		vendor
Gemfile.lock	app		db		log		test
README.rdoc	config		doc		public		tmp

Windows Only: if you're running this tutorial directly on a Windows system, you'll need to use dir instead of ls anywhere in these instructions where you're asked to list files.

Step 1a: (Linux only) Enable javascript runtime

Find the line in your Gemfile that has # gem 'therubyracer', :platforms => :ruby and uncomment that line. This allows your system to identify the appropriate javascript runtime.

Now save the Gemfile and run bundle install. This tells bundler to update your dependencies to reflect the change in your Gemfile.

Alternatively, a Node.js runtime will be resolved without adding therubyracer. Joyent maintains simple instructions for installing Node.js with various Linux package managers.

Step 2: Initialize your git repository

Now, let's turn the application directory into a git repository. Type the following:

git init .

Then you should see something like this:

Initialized empty Git repository in /Users/camper/hydra-works-demo/.git/

Next, we'll add all the files rails created into the repository. This way we can jump back to this state later if the need arises.

git add .
git commit -m "Initial rails application"

Next Step

Go on to Lesson: Add the Hydra Dependencies or return to the Dive into Hydra-Works page.