Allow specifying navigation tab for controllers

app/controllers/application_controller.rb

@@ -7,6 +7,7 @@ class ApplicationController < ActionController::Base
   # used, or custom layout method needs to be defined.
 
   helper_method :current_user_disguised?
+  helper_method :current_tab
 
   before_action :authenticate_user!
 
@@ -42,6 +43,16 @@ class ApplicationController < ActionController::Base
     new_user_session_path
   end
 
+  class << self
+    attr_reader :navigation_menu_tab
+    def navigation_tab(name)
+      @navigation_menu_tab = name.to_s
+    end
+  end
+  def current_tab
+    self.class.navigation_menu_tab || controller_name
+  end
+
   private
 
   def rescue_turbo(exception)

app/controllers/units/defaults_controller.rb

@@ -1,4 +1,6 @@
 class Units::DefaultsController < ApplicationController
+  navigation_tab :units
+
   before_action except: :index do
     raise AccessForbidden unless current_user.at_least(:admin)
   end