user roles are fetching in create user form but not adding user role in database

    <!-- /.content-header -->
  <div class="container">
    <div class="columns m-t-10">
      <div class="column">
      </div>
    </div>
    <hr class="m-t-0">
    <form action="{{route('users.store')}}" method="POST">
      {{csrf_field()}}
      <div class="columns">
        <div class="column">
          <div>
            <label for="name" class="label">Name</label>
              <input type="text" class="input" name="name" id="name">
            
          </div>

          <div>
            <label for="email" class="label">Email:</label>
              <input type="text" class="input" name="email" id="email">
          </div>
          <div >
            <label for="password" class="label">Password</label>
              <input type="text" class="input" name="password" id="password" placeholder="enter password">
              
            </p>
          </div>
        </div> <!-- end of .column -->

        <div class="column">
          <label for="roles" class="label">Roles:</label>
       

            @foreach ($roles as $role)
              <div class="field">
              <label><input type="checkbox" value="{{$role->id}}">   {{$role->display_name}} </label>
              </div>
            @endforeach
        </div>

      </div> <!-- end of .columns for forms -->
      <div class="columns">
        <div class="column">
          <hr />
          <button class="btn btn-primary" style="width: 250px;">Create New User</button>
        </div>
      </div>
    </form>
  </div> <!-- end of .flex-container -->







/*my controller is here */
<?php

namespace App\Http\Controllers\manage;
use App\Http\Controllers\Controller;

use Illuminate\Http\Request;
use App\User;
use App\Role;
use DB;
use Session;
use Hash;
use Input;

class UserController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
      $users = User::orderBy('id', 'desc')->paginate(10);
      return view('manage.users.index')->withUsers($users);
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create()
    {
      $roles = Role::all();
      return view('manage.users.create')->withRoles($roles);
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(Request $request)
    {
      $this->validateWith([
        'name' => 'required|max:255',
        'email' => 'required|email|unique:users'
      ]);

      if (!empty($request->password)) {
        $password = trim($request->password);
      } else {
        # set the manual password
        $length = 10;
        $keyspace = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';
        $str = '';
        $max = mb_strlen($keyspace, '8bit') - 1;
        for ($i = 0; $i < $length; ++$i) {
            $str .= $keyspace[random_int(0, $max)];
        }
        $password = $str;
      }

      $user = new User();
      $user->name = $request->name;
      $user->email = $request->email;
      $user->password = Hash::make($password);
      $user->save();

      if ($request->roles) {
        $user->syncRoles(explode(',', $request->roles));
      }

      return redirect()->route('users.show', $user->id);

      // if () {
      //
      // } else {
      //   Session::flash('danger', 'Sorry a problem occurred while creating this user.');
      //   return redirect()->route('users.create');
      // }
    }

    /**
     * Display the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function show($id)
    {
      $user = User::where('id', $id)->with('roles')->first();
      return view("manage.users.show")->withUser($user);
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function edit($id)
    {
      $roles = Role::all();
      $user = User::where('id', $id)->with('roles')->first();
      return view("manage.users.edit")->withUser($user)->withRoles($roles);
    }

    /**
     * Update the specified resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function update(Request $request, $id)
    {
      $this->validateWith([
        'name' => 'required|max:255',
        'email' => 'required|email|unique:users,email,'.$id
      ]);

      $user = User::findOrFail($id);
      $user->name = $request->name;
      $user->email = $request->email;
      if ($request->password_options == 'auto') {
        $length = 10;
        $keyspace = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';
        $str = '';
        $max = mb_strlen($keyspace, '8bit') - 1;
        for ($i = 0; $i < $length; ++$i) {
            $str .= $keyspace[random_int(0, $max)];
        }
        $user->password = Hash::make($str);
      } elseif ($request->password_options == 'manual') {
        $user->password = Hash::make($request->password);
      }
      $user->save();

      $user->syncRoles(explode(',', $request->roles));
      return redirect()->route('users.show', $id);

      // if () {
      //   return redirect()->route('users.show', $id);
      // } else {
      //   Session::flash('error', 'There was a problem saving the updated user info to the database. Try again later.');
      //   return redirect()->route('users.edit', $id);
      // }
    }

    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function destroy($id)
    {
        //
    }
}