In this lesson, you will learn how to create your first Ruby on Rails application.
How to Generate a Rails Application Using
To start, use your terminal navigate to the folder that you’d like to create your Rails application in. For me, that’s my
Dev folder. I can navigate to this directory using the following statement;
Once you have navigated to the desired directory, it is time to generate a boilerplate Rails application.
You can generate the Rails application with the
rails new command followed by the name of your application. The application name cannot contain spaces. In my case, I will name my application
We will also pass in a few optional parameters to our
rails new statement. Specifically, we will add:
-T- this tells Rails to avoid installing its test framework, which takes up unnecessary space since we will not be using it in this course
--database=postgresql- without this parameter, Rails will use the SQLite database, a smaller, less feature-rich database than the PostgreSQL database that we installed in the last lesson
Here’s what the full statement looks like:
rails new rails_course -T --database=postgresql
After you run this statement, Rails will create dozens of files and install all of the dependencies it requires. This is likely to take several minutes.
Your terminal may print the following statement after running the
rails new command:
Run `bundle install` to install missing gems.
If this is the case, then navigate into your new application’s directory with
cd rails_course and run the
bundle install command to install the gems that you are missing.
You can now open the directory in using your Mac’s Finder application with the
open . statement. You’ll see many folders that have just been created using the
rails new command, including
How to Start a Rails Server Using
Now that we have created our boilerplate Rails application, we need to start a Rails server to actually view the application.
We will need to install
yarn to be able to start this server. We can install
yarn using Homebrew with the following command:
brew install yarn
Now that this is done, You can start a rails server with the following command:
Note that if you receive any errors while running the
rails s command, then the error message will contain instructions on how to fix the error.
As an example, I originally encountered an error while running this on my new machine. The error message contained the following excerpt:
Please run rails webpacker:install. Accordingly, I fixed the error by running the
rails webpacker:install command.
rails s command is successful, then your terminal should print a few lines of text that end in
Use CTRL+C to stop. This means that your server is now running, and you can view your application by typing the URL
[http://127.0.0.1:3000/](http://127.0.0.1:3000/) into your browser.