Admin panel (#496)

* Added the administrator role and functionality that comes with it  (#403)

* GRN-20: Added roles to the user model

* GRN-75: Added a view for admins to see their users

* GRN-77: Added Edit/Delete/Promote ability for admins

* GRN-71: Added admin account by default

* Changed the way locales are shown

* Updated the rest of the locales

* Changed the way available_locales are defined

* Updated locales in Russian

* Updated locaales for German

* Update user.rb

* Update admins.js

* GRN-15: Added the ability to change color and image from admin interface (#425)

* GRN-20: Added roles to the user model

* GRN-75: Added a view for admins to see their users

* GRN-77: Added Edit/Delete/Promote ability for admins

* GRN-71: Added admin account by default

* Changed the way locales are shown

* Updated the rest of the locales

* Changed the way available_locales are defined

* Updated locales in Russian

* Updated locaales for German

* GRN-15: Added the ability for admins to customize color and image

* Update user.rb

* Update user.rb

* Update routes.rb

* Update admins_controller.rb

* GRN-87:Added a super admin role and made changes to how to the design works (#430)

* GRN-20: Added roles to the user model

* GRN-75: Added a view for admins to see their users

* GRN-77: Added Edit/Delete/Promote ability for admins

* GRN-71: Added admin account by default

* Changed the way locales are shown

* Updated the rest of the locales

* Changed the way available_locales are defined

* Updated locales in Russian

* Updated locaales for German

* GRN-15: Added the ability for admins to customize color and image

* Added the super admin and completed the design tab

* Update user.rb

* Update themes_controller_spec.rb

* Update routes.rb

* Update admins_controller.rb

* Removed duplicated code that broke the build after last merge

* GRN-78: Restructured some of the views to make the UI more consistent and responsive (#435)

* GRN-20: Added roles to the user model

* GRN-75: Added a view for admins to see their users

* GRN-77: Added Edit/Delete/Promote ability for admins

* GRN-71: Added admin account by default

* GRN-15: Added the ability for admins to customize color and image

* Added the super admin and completed the design tab

* GRN-78: Cleaned up buttons and moved signin to its own page

* GRN-78: Moved the Rooms and Recordings link to nav bar

* Merge fix

* Views restructure fix (#458)

* Added cache to gitlab-ci.yml

* Restructured seed

* GRN2-99 -> GRN2-106: UI cleanup and refactoring (#478)

* GRN2-98: Change Fullname to Full name

* GRN2-105: Changed View Users to Manage Users

* GRN2-101/103: Updated email to match branding

* GRN2-100: Updated Email Sent flash to be more descriptive

* GRN2-104: Redirect user to sign in page w/ flash after clicking activation link

* GRN2-102: Changed the wording in the verification email

* GRN2-99: Added email form validation

* GRN2-106: Cleaned up Users list front end

* Fixes to rake and admin password validator for passing rubocop

* GRN2-113: Fixed issues with admin panel (#479)

* GRN2-116: Code clean up after restructure of views (#482)

* Removed unused references

* Rubocop

* Added pagination to admin view (#483)

* GRN2-114: Added the ability for admins to ban/unban users (#487)

* Added the ability for admins to ban and unban users

* Update sessions_helper.rb

*  Merge branch 'master' into admin-panel  (#492)

* Updated rubocop gem

* Updated rubocop and fixed issues (#490)

* Rubocop fixes

* GRN2-122: Updated sign in flow for admins and switch design tab to site settings (#489)

* Switched design tab to site settings

* Update _header with spaces instead of tabs

* Added more test cases to increase coverage (#494)

app/controllers/application_controller.rb

@@ -20,10 +20,13 @@ require 'bigbluebutton_api'
 
 class ApplicationController < ActionController::Base
   include SessionsHelper
+  include ThemingHelper
 
   before_action :migration_error?
   before_action :set_locale
+  before_action :check_admin_password
   before_action :set_user_domain
+  before_action :check_if_unbanned
 
   # Force SSL for loadbalancer configurations.
   before_action :redirect_to_https
@@ -102,6 +105,21 @@ class ApplicationController < ActionController::Base
     }
   end
 
+  # Manually deal with 401 errors
+  rescue_from CanCan::AccessDenied do |_exception|
+    render "errors/not_found"
+  end
+
+  # Checks to make sure that the admin has changed his password from the default
+  def check_admin_password
+    if current_user&.has_role?(:admin) && current_user&.greenlight_account? &&
+       current_user&.authenticate(Rails.configuration.admin_password_default)
+
+      flash.now[:alert] = I18n.t("default_admin",
+        edit_link: edit_user_path(user_uid: current_user.uid) + "?setting=password").html_safe
+    end
+  end
+
   def redirect_to_https
     if Rails.configuration.loadbalanced_configuration && request.headers["X-Forwarded-Proto"] == "http"
       redirect_to protocol: "https://"
@@ -116,4 +134,13 @@ class ApplicationController < ActionController::Base
     end
   end
   helper_method :set_user_domain
+
+  # Checks if the user is banned and logs him out if he is
+  def check_if_unbanned
+    if current_user&.has_role?(:denied)
+      session.delete(:user_id)
+      redirect_to unauthorized_path
+    end
+  end
+  helper_method :check_if_unbanned
 end