Make the AA installer interactive - Issue activeadmin#2513

 - The installer asks the user for input in wheter or not he wants Devise and the name of the user class;
 - Creates an option for no interactivity, which is used in our tests
 - Updates the documentation

docs/0-installation.md

@@ -21,24 +21,32 @@ that can be injected into your existing Ruby on Rails application.
 
 ## Setting up Active Admin
 
-After installing the gem, you need to run the generator. Here are your options:
+After installing the gem, you need to run the generator. It will check with you
+things like whether you want to use Devise or not and the name of the User class.
 
-* If you don't want to use Devise, run it with `--skip-users`:
+  ```sh
+  rails g active_admin:install
+  ```
+
+If you don't want this interaction, run it with `--no_interaction` and we will use
+default values and create an `AdminUser` class to use with Devise
 
   ```sh
-  rails g active_admin:install --skip-users
+  rails g active_admin:install --no_interaction
   ```
 
-* If you want to use an existing user class, provide it as an argument:
+Here are your other options and they all skip their respective interactive questions:
+
+* If you don't want to use Devise, run it with `--skip-users`:
 
   ```sh
-  rails g active_admin:install User
+  rails g active_admin:install --skip-users
   ```
 
-* Otherwise, with no arguments we will create an `AdminUser` class to use with Devise:
+* If you want to use an existing user class, provide it as an argument:
 
   ```sh
-  rails g active_admin:install
+  rails g active_admin:install User
   ```
 
 The generator adds these core files, among others:

lib/generators/active_admin/install/install_generator.rb

@@ -6,15 +6,34 @@ class InstallGenerator < ActiveRecord::Generators::Base
       desc "Installs Active Admin and generates the necessary migrations"
       argument :name, type: :string, default: "AdminUser"
 
-      hook_for :users, default: "devise", desc: "Admin user generator to run. Skip with --skip-users"
+      class_option "skip-users", type: :boolean, default: false, desc: "No authentication"
+      class_option :no_interaction, type: :boolean, default: false, desc: "No User Interaction"
       class_option :skip_comments, type: :boolean, default: false, desc: "Skip installation of comments"
       class_option :use_webpacker, type: :boolean, default: false, desc: "Use Webpacker assets instead of Sprockets"
 
       source_root File.expand_path("templates", __dir__)
 
+      def interactive_setup
+        @use_authentication_method = true
+        return if options[:no_interaction]
+
+        unless options["skip-users"]
+          if yes?("Do you want authentication with Devise? [y for yes]")
+            @name = ask("What would you like the user model to be called? [Press Enter for default: AdminUser]")
+          else
+            @use_authentication_method = false
+          end
+        end
+      end
+
+      def setup_devise
+        if @use_authentication_method
+          generate("active_admin:devise", @name) unless options["skip-users"]
+        end
+      end
+
       def copy_initializer
-        @underscored_user_name = name.underscore.gsub("/", "_")
-        @use_authentication_method = options[:users].present?
+        @underscored_user_name = @name.underscore.gsub("/", "_")
         @skip_comments = options[:skip_comments]
         @use_webpacker = options[:use_webpacker]
         template "active_admin.rb.erb", "config/initializers/active_admin.rb"
@@ -23,14 +42,14 @@ def copy_initializer
       def setup_directory
         empty_directory "app/admin"
         template "dashboard.rb", "app/admin/dashboard.rb"
-        if options[:users].present?
-          @user_class = name
-          template "admin_users.rb.erb", "app/admin/#{name.underscore.pluralize}.rb"
+        if @use_authentication_method
+          @user_class = @name
+          template "admin_users.rb.erb", "app/admin/#{@name.underscore.pluralize}.rb"
         end
       end
 
       def setup_routes
-        if options[:users] # Ensure Active Admin routes occur after Devise routes so that Devise has higher priority
+        if @use_authentication_method # Ensure Active Admin routes occur after Devise routes so that Devise has higher priority
           inject_into_file "config/routes.rb", "\n  ActiveAdmin.routes(self)", after: /devise_for .*, ActiveAdmin::Devise\.config/
         else
           route "ActiveAdmin.routes(self)"

spec/support/rails_template.rb

@@ -75,7 +75,7 @@
 end
 
 # Setup Active Admin
-generate "active_admin:install#{" --use-webpacker" if webpacker_app}"
+generate "active_admin:install --no_interaction#{" --use-webpacker" if webpacker_app}"
 
 # Force strong parameters to raise exceptions
 inject_into_file "config/application.rb", after: "class Application < Rails::Application" do