Goals

Now that the structure is complete, lets make the flow work smoothly.

Currently when you go to http://localhost:4000 you see the “Welcome aboard” message.

It would be easier to use our app if http://localhost:4000 went directly to the topics list.

In this step we’ll make that happen and learn a bit about routes in Rails.

Steps

Step 1: Add a root route

Open the file web/router.ex in an editor (In the InstallFest yesterday, we suggested that you install and use Atom as your editor).

Look for the line get "/", PageController, :index in the lower two thirds of the file, and change PageController to say TopicController. When you are done that block of code should look like this:

```scope “/”, TestApp do pipe_through :browser # Use the default browser stack

resources “/topics”, TopicController get “/”, TopicController, :index end


### Step 2: Confirm your changes
Go back to http://localhost:4000/. You should be taken to the topics list automatically.

Explanation

`get "/", TopicController, :index` is a Phoenix route that tells the app when a GET request comes in for the root of the site (that is, the domain without anything after the /), to user the `TopicController` and the `:index` method. The `index` method is the topics list page.

Phoenix routes control how URLs get matched with the code on the server. It's similar to how houses and apartments have addresses. You can think of each controller as a street, and each method in that controller as a house.

The file `web/router.ex` is like an address directory listing all the possible addresses and which code goes with each one. `routes.rb` uses some shortcuts so that it doesn't always show all the possible URLs. To explore the URLs in more detail we can use the terminal.

At the terminal type `mix phoenix.routes`. You should get something that looks like this:

mix phoenix.routes topic_path GET /topics TestApp.TopicController :index topic_path GET /topics/:id/edit TestApp.TopicController :edit topic_path GET /topics/new TestApp.TopicController :new topic_path GET /topics/:id TestApp.TopicController :show topic_path POST /topics TestApp.TopicController :create topic_path PATCH /topics/:id TestApp.TopicController :update PUT /topics/:id TestApp.TopicController :update topic_path DELETE /topics/:id TestApp.TopicController :delete topic_path GET / TestApp.TopicController :index ``` This shows all the URLs your application responds to. The parts of the URLs that start with colons are variables so :id means the id number of the record.

Deploying

Before the next step, you could try deploying your app to Heroku!

Go on to Deploying To Heroku