invoiceninja/database/migrations/2015_05_27_121828_add_tasks.php

<?php

use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class AddTasks extends Migration
{

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('tasks', function ($table) {
            $table->increments('id');
            $table->unsignedInteger('user_id');
            $table->unsignedInteger('account_id')->index();
            $table->unsignedInteger('client_id')->nullable();
            $table->unsignedInteger('invoice_id')->nullable();
            $table->timestamps();
            $table->softDeletes();

            $table->timestamp('start_time')->nullable();
            $table->integer('duration')->nullable();
            $table->string('description')->nullable();
            $table->boolean('is_deleted')->default(false);

            $table->foreign('account_id')->references('id')->on('accounts')->onDelete('cascade');
            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
            $table->foreign('invoice_id')->references('id')->on('invoices')->onDelete('cascade');
            $table->foreign('client_id')->references('id')->on('clients')->onDelete('cascade');
            
            $table->unsignedInteger('public_id')->index();
            $table->unique(array('account_id','public_id'));
        });

        Schema::dropIfExists('timesheets');
        Schema::dropIfExists('timesheet_events');
        Schema::dropIfExists('timesheet_event_sources');
        Schema::dropIfExists('project_codes');
        Schema::dropIfExists('projects');
    }

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