Adding instructions for getting started with API-only apps (#1008)

* Link to instructions for API-only app
* Add note about root route in Getting Started
* Adding additional notes for setup for API-only apps
* Editing note that links to guide

README.md

@@ -61,6 +61,9 @@ $ rails generate administrate:install
 Restart your server, and visit http://localhost:3000/admin
 to see your new dashboard in action.
 
+For more detailed instructions or to make it work with Rails API-only applications, please go through the ['Getting Started` guide](https://administrate-prototype.herokuapp.com/getting_started).
+
+
 ## Create Additional Dashboards
 
 In order to create additional dashboards, pass in the resource name to

docs/getting_started.md

@@ -29,6 +29,20 @@ The `Admin::ApplicationController` can be customized to add
 authentication logic, authorization, pagination,
 or other controller-level concerns.
 
+You will also want to add a `root` route to show a dashboard when you go to `/admin`.
+
+```ruby
+Rails.application.routes.draw do
+  namespace :admin do
+    # Add dashboard for your models here
+    resources :customers,
+    resources :orders
+
+    root to: "customers#index" # <--- Root route
+  end
+ end
+ ```
+
 The routes can be customized to show or hide
 different models on the dashboard.
 
@@ -62,7 +76,9 @@ end
 ## Rails API
 
 Since Rails 5.0, we've been able to have API only applications. Yet, sometimes
-we still want to have an admin. To get this working, please update this config:
+we still want to have an admin. 
+
+To get this working, we recommend updating this config:
 
 ```ruby
 # config/application.rb
@@ -74,3 +90,26 @@ also don't use your `ApplicationController`. Instead, Administrate provides its
 own. Meaning you're free to specify `ActionController::API` as your parent
 controller to make sure no flash, session, or cookie middleware is used by your
 API.
+
+Alternatively, if your application needs to have `config.api_only = true`, we recommend you add the following lines to your `config/application.rb`
+
+```ruby
+# Enable Flash, Cookies, MethodOverride for Administrate Gem
+config.middleware.use ActionDispatch::Flash
+config.session_store :cookie_store
+config.middleware.use ActionDispatch::Cookies
+config.middleware.use ActionDispatch::Session::CookieStore, config.session_options
+config.middleware.use ::Rack::MethodOverride
+```
+
+You must also ensure that the all the required controller actions are available and accessible as routes since generators in API-only applications only generate some of the required actions. Here is an example:
+
+```ruby
+# routes.rb
+namespace :admin do
+  resources name, only: %i(index show new create edit update destroy)
+end
+
+# names_controller.rb
+# Ensure each of those methods are defined
+```