The --without production option prevents the installation of the production gems, which in this case is just the PostgreSQL gem pg. (If Bundler complains about

try adding gem ’rb-readline’ to your Gemfile.)

      Finally, we’ll put the demo app under version control. Recall that the rails command generates a default .gitignore file, but depending on your system you may find the augmented file from Listing 1.7 to be more convenient. Then initialize a Git repository and make the first commit:

You can also optionally create a new repository (Figure 2.1) and push it up to GitHub:

(As with the first app, take care not to initialize the GitHub repository with a README file.)

Now we’re ready to start making the app itself. The typical first step when making a web application is to create a data model, which is a representation of the structures needed by our application. In our case, the demo app will be a microblog, with only users and short (micro)posts. Thus, we’ll begin with a model for users of the app (Section 2.1.1), then we’ll add a model for microposts (Section 2.1.2).