Add users management to site settings (#126)

app/helpers/application_helper.rb

@@ -1,12 +1,27 @@
 module ApplicationHelper
-  def authenticate_admin
+  def check_user_signed_in
     unless user_signed_in?
       flash[:alert] = t('backend.errors.not_logged_in')
       redirect_to new_user_session_path
+      
+      return false
+    end
+  end
+
+  def authenticate_admin
+    return if check_user_signed_in == false
+
+    unless current_user.admin?
+      flash[:alert] = t('backend.errors.not_enough_privileges')
+      redirect_to root_path
       return
     end
+  end
 
-    unless current_user.moderator? || current_user.admin?
+  def authenticate_power_user
+    return if check_user_signed_in == false
+
+    unless current_user.admin? or current_user.moderator?
       flash[:alert] = t('backend.errors.not_enough_privileges')
       redirect_to root_path
       return