ruby - Heroku Production Rails(3.2.3) Active admin(0.5) NoMethodError in create & update -

as working on active admin(0.5) rails 3.2.3 using multilingual support using globalise 3 .

when running application on local under development & production environment works great.

but when deployed on heroku production mode throwing me error same code using on local.

when click on create new page giving me below error:

nomethoderror in admin::hometemplatescontroller#new  undefined method `build_app_page' nil:nilclass rails.root: /app  application trace | framework trace | full trace app/admin/home_templates.rb:16:in `new' 

please find below code

activeadmin.register hometemplate      menu false   config.clear_action_items!      form :partial => "form"      controller         protect_from_forgery :except => :sort      def new       # @home_template  =hometemplate.new       # if !!current_ability.attributes_for(:create, hometemplate)[:app_instance_id]       #   @valid_parents = apppage.where("app_instance_id = ? , parent_id null", current_ability.attributes_for(:create, hometemplate)[:app_instance_id])       # end       @home_template.build_app_page     end      def create        # if !!current_ability.attributes_for(:create, hometemplate)[:app_instance_id]       #   @valid_parents = apppage.where("app_instance_id = ? , parent_id null", current_ability.attributes_for(:create, hometemplate)[:app_instance_id])       # end       if @home_template.present?       @home_template.app_page.protected = false;       @home_template.app_page.hidden = false;       @home_template.app_page.app_instance = @home_template.app_instance;       create!       end     end      def update       #@home_template = hometemplate.find(params[:id])       @valid_parents = apppage.where("app_instance_id = ? , parent_id null", @home_template.app_page.app_instance_id)       update!     end      def edit        # if !!current_ability.attributes_for(:edit, hometemplate)[:app_instance_id]        #   @valid_parents = apppage.where("app_instance_id = ? , parent_id null", current_ability.attributes_for(:edit, hometemplate)[:app_instance_id])        #   rails.logger.info( @valid_parents)        #   rails.logger.info( current_ability.attributes_for(:edit, hometemplate)[:app_instance_id])        # end        rails.logger.info( "home template outside")        #@home_template = hometemplate.find(params[:id])        @valid_parents = apppage.where("app_instance_id = ? , parent_id null", @home_template.app_page.app_instance_id)        rails.logger.info(@valid_parents)     end    end    collection_action :sort, :method => :post     if(params[:ids])       params[:ids].each_with_index |id, index|         app_page = apppage.find(id)         app_page.move_to_child_of app_page.parent_id if can? :update, app_page.templatable       end     end     head 200   end  end 

i tried connect console through heroku & fetching models.

i checked postgres database on local in production ode & worked charm.

right using sqlite & postgres on local & heroku postgres.

your & guidance highly appreciable & deserves hat off side.

please let me know if more details required.

right using polymorphic association

as below

class hometemplate < activerecord::base    include belongstoappinstance     has_one :app_page, :as => :templatable   has_many :home_banner_images, :dependent => :destroy    accepts_nested_attributes_for :home_banner_images, :allow_destroy => true   accepts_nested_attributes_for :app_page   validates_presence_of :app_page  end 

apppages as:

class apppage < activerecord::base    include belongstoappinstance   belongs_to :last_modified_by, :class_name => "adminuser"   validates_presence_of :last_modified_by    belongs_to :templatable, :polymorphic => true, :dependent => :destroy   has_many :app_page_callouts   acts_as_nested_set    attr_readonly :hidden   attr_readonly :protected    default_scope :order => 'lft asc'    validates_presence_of :name   #validates_uniqueness_of :name, :scope => :app_instance_id   validates_uniqueness_of :app_page_role, :scope => :app_instance_id    mount_uploader :related_pdf, pdfuploader    validate :parent_must_belong_to_same_app_instance   #validates_inclusion_of :linked_model, :in => apppage.allowable_linked_models, :unless => proc.new {|app_page| app_page.linked_model.blank? }   attr_accessible :name,:subtitle,:body,:app_page_attributes,                   :app_instance_id,:app_page_role,:related_pdf,                   :parent_id,:translations_attributes,                   :last_modified_by,:app_instance,:sort,:view_controller,:hidden,:protected,:app_page_callouts,:parent   active_admin_translates :name,:subtitle,:body   #validates_globalized_uniqueness_of :name,:scope => :locale   def parent_must_belong_to_same_app_instance     if !self.parent_id.nil? && self.parent.app_instance_id != self.app_instance_id        errors.add(:parent_id, "the parent must belong same app instance.")     end   end   def set_view_controller     if self.view_controller.nil?       self.view_controller = "detail"     end   end end