_form.haml

= form_for [:admin, navigation_link] do |f|
  .row.mt20
    .col-sm-12
      .panel.panel-default
        .panel-heading
          %h4.panel-title= title
        .panel-body.form-horizontal
          .form-group
            = f.label :name, class: "col-lg-2 col-md-2 col-sm-12 control-label"
            .col-lg-10.col-md-10
              = f.text_field :name, class: "form-control"
          .form-group
            = f.label :position, class: "col-lg-2 col-md-2 control-label"
            .col-md-1
              = f.text_field :position, class: "form-control"
            .col-md-4
              = f.label :path, class: "col-lg-2 col-md-2 col-sm-12 control-label"
              = f.select :path, Page.all.collect {|p|[p.url_link_name, p.slug  ]  } << ["blogs", "/blogs"] << ["none", "#"]
          .form-group
            = f.label "Parent", class: "col-lg-2 col-md-2 col-sm-12 control-label"
            .col-lg-10.col-md-10
              = f.select :navigation_link_id, @navigation_links.collect { |p| [ p.name, p.id  ]  } << ["Top", nil], {class: 'form-control'}, selected: f.object.name

navigation_link.rb

class NavigationLink < ActiveRecord::Base
  belongs_to :parent, :class_name => "navigation_link"
  has_many :navigation_links, :foreign_key => "navigation_link_id"

  def has_children?
    !self.navigation_links.empty?
  end

  def is_not_child?
    self.navigation_link_id.nil?
  end
end

navigation_links_controller.rb

class Admin::NavigationLinksController < Admin::PanelController
  def index
    @navigation_links = NavigationLink.all
    @navigation_link = NavigationLink.new
  end

  def create
    @navigation_link = NavigationLink.new(navigation_link_params)
    if @navigation_link.save
      redirect_to admin_navigation_links_path
      flash[:success] = 'Link created'
    else
      render :index
      flash[:danger] = 'There was an error'
    end
  end

  def update
    find_navigation_link
    if @navigation_link.update(navigation_link_params)
      redirect_to admin_navigation_links_path
      flash[:success] =  "Link updated"
    else
    end
  end

  def destroy
    @navigation_link = NavigationLink.find(params[:id])
    @navigation_link.destroy
    redirect_to admin_navigation_links_path
    flash[:danger] = "Link deleted!"
  end

  private

  def find_navigation_link
    @navigation_link = NavigationLink.find(params[:id])
  end

  def navigation_link_params
    params.require(:navigation_link).permit!
  end
end

post.rb

[1] pry(#<Admin::NavigationLinksController>)> params
=> <ActionController::Parameters {"utf8"=>"✓", "authenticity_token"=>"/py7B4Oy+X8kTaf62AyeJISWLuT4B9Ztot/mh/QaD6Hn16k/t4KpjW4+aWwdTFng3erGI1t9IqkhKbn9FMEyMg==", "navigation_link"=>{"name"=>"zzzz22", "position"=>"2", "path"=>"zzzzz", "navigation_link_id"=>"18"}, "commit"=>"Save Link", "controller"=>"admin/navigation_links", "action"=>"create"} permitted: false>

schema.rb

  create_table "navigation_links", force: :cascade do |t|
    t.string   "path"
    t.string   "name"
    t.integer  "navigation_link_id"
    t.datetime "created_at",         null: false
    t.datetime "updated_at",         null: false
    t.boolean  "sublink"
    t.integer  "position"
    t.integer  "page_id"
    t.index ["navigation_link_id"], name: "index_navigation_links_on_navigation_link_id", using: :btree
  end