SyntaxError in MusicsController#new - ruby-on-rails

Question

I want to Save Multiple Check box values to Database.When i run this code I got an error:- premature end of char-class: /[\][\]\"]/
and when I click on check box for selecting any check box value then it should display the details of that check box values below that page on only.
This is my code:
music.rb
class Music < ActiveRecord::Base
before_save do
self.genre.gsub!(/[\][\]\"]/,"") if attribute_present?("genre")
end
end
musics_controller.rb
class MusicsController < ApplicationController
before_action :set_music, only: [:show, :edit, :update, :destroy]
def index
#musics = Music.all
end
def show
end
def new
#music = Music.new
end
def edit
end
def create
#music = Music.new(music_params)
respond_to do |format|
if #music.save
format.html { redirect_to #music, notice: 'Music was successfully created.' }
format.json { render :show, status: :created, location: #music }
else
format.html { render :new }
format.json { render json: #music.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if #music.update(music_params)
format.html { redirect_to #music, notice: 'Music was successfully updated.' }
format.json { render :show, status: :ok, location: #music }
else
format.html { render :edit }
format.json { render json: #music.errors, status: :unprocessable_entity }
end
end
end
def destroy
#music.destroy
respond_to do |format|
format.html { redirect_to musics_url, notice: 'Music was successfully destroyed.' }
format.json { head :no_content }
end
end
private
def set_music
#music = Music.find(params[:id])
end
def music_params
params.require(:music).permit(:title, :artist, genre:[])
end
end