Using custom schema builder with laravel-cassandra

I'm using this library shso/laravel-cassandra to access my cassandra instance from Lumen and everything is working fine. but when I try to use Laravel migrate I get this exception

[Symfony\Component\Debug\Exception\FatalThrowableError]  
  Call to a member function prepare() on null              


Exception trace:
 () at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Connection.php:326
 Illuminate\Database\Connection->Illuminate\Database\{closure}() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Connection.php:657
 Illuminate\Database\Connection->runQueryCallback() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Connection.php:624
 Illuminate\Database\Connection->run() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Connection.php:333
 Illuminate\Database\Connection->select() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Connection.php:304
 Illuminate\Database\Connection->selectFromWriteConnection() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Schema/Builder.php:75
 Illuminate\Database\Schema\Builder->hasTable() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Migrations/DatabaseMigrationRepository.php:169
 Illuminate\Database\Migrations\DatabaseMigrationRepository->repositoryExists() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Migrations/Migrator.php:583
 Illuminate\Database\Migrations\Migrator->repositoryExists() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Console/Migrations/MigrateCommand.php:91
 Illuminate\Database\Console\Migrations\MigrateCommand->prepareDatabase() at /home/masoud/Codes/TheSite/api/vendor/illuminate/database/Console/Migrations/MigrateCommand.php:63
 Illuminate\Database\Console\Migrations\MigrateCommand->handle() at n/a:n/a
 call_user_func_array() at /home/masoud/Codes/TheSite/api/vendor/illuminate/container/BoundMethod.php:32
 Illuminate\Container\BoundMethod::Illuminate\Container\{closure}() at /home/masoud/Codes/TheSite/api/vendor/illuminate/container/BoundMethod.php:90
 Illuminate\Container\BoundMethod::callBoundMethod() at /home/masoud/Codes/TheSite/api/vendor/illuminate/container/BoundMethod.php:34
 Illuminate\Container\BoundMethod::call() at /home/masoud/Codes/TheSite/api/vendor/illuminate/container/Container.php:576
 Illuminate\Container\Container->call() at /home/masoud/Codes/TheSite/api/vendor/illuminate/console/Command.php:183
 Illuminate\Console\Command->execute() at /home/masoud/Codes/TheSite/api/vendor/symfony/console/Command/Command.php:255
 Symfony\Component\Console\Command\Command->run() at /home/masoud/Codes/TheSite/api/vendor/illuminate/console/Command.php:170
 Illuminate\Console\Command->run() at /home/masoud/Codes/TheSite/api/vendor/symfony/console/Application.php:921
 Symfony\Component\Console\Application->doRunCommand() at /home/masoud/Codes/TheSite/api/vendor/symfony/console/Application.php:273
 Symfony\Component\Console\Application->doRun() at /home/masoud/Codes/TheSite/api/vendor/symfony/console/Application.php:149
 Symfony\Component\Console\Application->run() at /home/masoud/Codes/TheSite/api/vendor/illuminate/console/Application.php:90
 Illuminate\Console\Application->run() at /home/masoud/Codes/TheSite/api/vendor/laravel/lumen-framework/src/Console/Kernel.php:115
 Laravel\Lumen\Console\Kernel->handle() at /home/masoud/Codes/TheSite/api/artisan:35

This is the PHP code I wrote:

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;
use ShSo\Lacassa\Schema\Grammar;

class CreateUsersByEmail extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        DB::connection()->setSchemaGrammar(new ShSo\Lacassa\Schema\Grammar());
        $schema = DB::connection()->getSchemaBuilder();
        $schema->blueprintResolver(function($table, $callback) {
            return new \ShSo\Lacassa\Schema\Blueprint($table, $callback);
        });

        $schema->create('users_by_email', function ($table) {
            $table->uuid('id');     //User ID
            $table->varchar("email");
            $table->varchar("first_name");
            $table->varchar("last_name");
            $table->timestamp("email_verified_at");
            $table->varchar("password");
            $table->varchar("token");
            $table->timestamp("created_at");
            $table->timestamp("updated_at");
            $table->primary("email");
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('users_by_email');
    }
}

I couldn't find any thing on google and I haven't been able to figure out what I'm doing wrong. any help is appreciated.

via Chebli Mohamed