public function up()
{
    Schema::create('contracts', function (Blueprint $table) {
        $table->increments('id');
        $table->string('java', 191)->nullable();
        $table->unsignedInteger('method_payment');
        $table->integer('kpi_dni')->nullable();
        $table->integer('kpi_ruc')->nullable();
        $table->integer('kpi_pos')->nullable();
        $table->integer('kpi_out')->nullable();

public function up()
{
    Schema::create('clients', function (Blueprint $table) {
        $table->increments('id');
        $table->string('name');
        $table->unsignedInteger('document_user')->default(1);
        $table->string('document')->unique();
        $table->string('phone')->nullable();
        $table->string('address')->nullable();
        $table->string('email')->nullable();
        $table->timestamps();

        $table->foreign('document_user')
            ->references('id')->on('document_users')
            ->onUpdate('cascade')
            ->onDelete('cascade');
    });
}

public function up()
{
    Schema::create('contract_client', function (Blueprint $table) {
        $table->increments('id');
        $table->integer('client_id')->unsigned();
        $table->integer('contract_id')->unsigned();
        $table->timestamps();
    });
}

class Contract extends Model

public function clients()
{
    return $this
        ->belongsToMany('AppClient')
        ->withTimestamps();
}

class Client extends Model{
public function contracts()
{
    return $this
        ->belongsToMany('AppContract')
        ->withTimestamps();
}

class ContractClient extends Model{
protected $table='contract_client';

protected $fillable = [
    'contract_id', 'client_id'
];
public function contract(){
    return $this->belongsToMany('AppContract', 'id', 'contract_id');
}
public function client(){
    return $this->belongsToMany('AppClient', 'id', 'client_id');
}

@foreach ($contracts as $contract)
                <tr>
                    <td>{{$contract->clients()->get()}}</td>