Split authentication concern from ApplicationController (#289)

* Split authentication concern from ApplicationController

* Remove empty space

* Rubocop fixes

app/controllers/application_controller.rb

@@ -1,43 +1,11 @@
 class ApplicationController < ActionController::Base
+  include Authentication
+
   # Only allow modern browsers supporting webp images, web push, badges, import maps, CSS nesting, and CSS :has.
   allow_browser versions: :modern
 
   private
 
-  def authenticate_user!
-    redirect_to new_session_path unless user_signed_in?
-  end
-
-  def current_user
-    Current.user || authenticate_user_from_session
-  end
-  helper_method :current_user
-
-  def current_family
-    current_user.family
-  end
-  helper_method :current_family
-
-  def authenticate_user_from_session
-    User.find_by(id: session[:user_id])
-  end
-
-  def user_signed_in?
-    current_user.present?
-  end
-  helper_method :user_signed_in?
-
-  def login(user)
-    Current.user = user
-    reset_session
-    session[:user_id] = user.id
-  end
-
-  def logout
-    Current.user = nil
-    reset_session
-  end
-
   def hosted_app?
     ENV["HOSTED"] == "true"
   end

app/controllers/concerns/authentication.rb

@@ -0,0 +1,42 @@
+module Authentication
+  extend ActiveSupport::Concern
+
+  included do
+    helper_method :current_user
+    helper_method :current_family
+    helper_method :user_signed_in?
+  end
+
+  private
+
+  def authenticate_user!
+    redirect_to new_session_path unless user_signed_in?
+  end
+
+  def current_user
+    Current.user || authenticate_user_from_session
+  end
+
+  def current_family
+    current_user.family
+  end
+
+  def authenticate_user_from_session
+    User.find_by(id: session[:user_id])
+  end
+
+  def user_signed_in?
+    current_user.present?
+  end
+
+  def login(user)
+    Current.user = user
+    reset_session
+    session[:user_id] = user.id
+  end
+
+  def logout
+    Current.user = nil
+    reset_session
+  end
+end