[8.x] Allow adding multiple columns after a column

[themsaid]

This PR allows:

Schema::table('users', function (Blueprint $table) {
    $table->after('remember_token', function ($table){
        $table->string('card_brand')->nullable();
        $table->string('card_last_four', 4)->nullable();
    });
});

The order of the columns will be:

• remember_token
• card_brand
• card_last_four

[taylorotwell]

Merged.

[ronssij]

This is a nice example implementing for assigning multiple nullable columns like this one.

Schema::table('users', function (Blueprint $table) {
   $table->nullable(function ($table){
      $table->string('lastname');
      $table->after('remember_token', function ($table){
          $table->string('card_brand');
          $table->string('card_last_four', 4);
      });
    });
});