artists_controller.rb

class ArtistsController < ApplicationController
  before_action :set_artist, only: [:show, :edit, :update, :destroy]
  skip_before_action :require_login, only: [:index, :show]

  def index
    @artists = Artist.all
  end

  def show
  end

  def new
    @artist = Artist.new
    authorize @artist
  end

  def edit
    authorize @artist
  end

  def create
    @artist = current_user.artists.build(artist_params)
    authorize @artist

    if @artist.save
      flash[:success] = 'Artist was successfully created.'
      redirect_to @artist
    else
      render :new
    end
  end

  def update
    authorize @artist

    if @artist.update(artist_params)
      flash[:success] = "Artist updated"
      redirect_to @artist
    else
      render :edit
    end
  end

  def destroy
    authorize @artist

    @artist.destroy
    flash[:success] = "Artist deleted"
    redirect_to artists_path
  end

  private
    def set_artist
      @artist = Artist.find(params[:id])
    end

    def artist_params
      params.require(:artist).permit(:name, :group)
    end
end