authorization with cancan

After looking at the ability.rb. I have allowed the admins to manage everything (that part works) but how do I allow the user to just, view and edit their own Logg using cancan? At the moment the users cannot view anything at all, not even their own created logg. But admins can do everything.

    class Logg < ActiveRecord::Base     has_and_belongs_to_many :user     end

      class User < ActiveRecord::Base         devise :database_authenticatable, :registerable,          :recoverable, :rememberable, :trackable, :validatable           ROLES = %w[admin moderator author banned]        has_and_belongs_to_many :logg    end

I have no User controller. I have the loggs controller:

    class LoggsController < ApplicationController

     before_action :set_logg, only: [:show, :edit, :update, :destroy]      load_and_authorize_resource

      respond_to :html

     def index      @loggs = Logg.all     respond_with(@loggs)      end

    def show     respond_with(@logg)     end

     def new     @logg = Logg.new     respond_with(@logg)      end

    def edit

    end

     def create     @logg = Logg.new(logg_params)     @logg.save     respond_with(@logg)      end

     def update     @logg.update(logg_params)     respond_with(@logg)     end

    def destroy      @logg.destroy     respond_with(@logg)     end

     private      def set_logg        @logg = Logg.find(params[:id])      end

     def logg_params       params.require(:logg).permit(:name, :date, :time, :whats_gone_well_this_week, :whats_not_gone_well_this_week, :learnt_anything_new, :what_would_you_like_to_improve, :anything_else)     end end

    class Ability     include CanCan::Ability     def initialize(user)

       if user.nil?       cannot :read, Logg       elsif user.admin?       can :manage, Logg      else       can :create, Logg, :user_id => user.id       can :update, Logg, :user_id => user.id       end       end     end