how to relate many to many relationship laravel code example

Example 1: laravel many to many migration

php artisan make:migration create_posts_users_table

Example 2: add data to laravel many to many relationship

1. $user->roles()->attach($roleId);

2. you may also pass an array of additional data to be inserted 
$user->roles()->attach($roleId, ['expires' => $expires]);

3. // Detach a single role from the user...
$user->roles()->detach($roleId);

4. // Detach all roles from the user...
$user->roles()->detach();

5. Any IDs that are not in the given array will be removed from the intermediate
	table
$user->roles()->sync([1, 2, 3]);

6. If you need to update an existing row in your pivot table, you may use 
  updateExistingPivot method. This method accepts the pivot record foreign 
  key and an array of attributes to update:

$user->roles()->updateExistingPivot($roleId, $attributes);