Remove Ransack from Exercise edit for tags

* Also improve Ransack usage of attributes and associations

app/models/application_record.rb

@@ -15,4 +15,12 @@ class ApplicationRecord < ActiveRecord::Base
       end
     end
   end
+
+  def self.ransackable_associations(_auth_object = nil)
+    []
+  end
+
+  def self.ransackable_attributes(_auth_object = nil)
+    []
+  end
 end