// Project belongsTo Customer

Project.findAll({
  include: [{
      model: Customer
  }]
})

{
  name: 'Project X',
  customer: {
   name: 'Customer Y',
   street: 'Paddington street'
  }
}

{
  name: 'Project X',
  customer_name: 'Customer Y',
  customer_street: 'Paddington street'
}

Project.findAll({
    include: [{
        model: Customer
    }]
}).then(projects => {
    return projects.map(project => {
        Object.keys(project.customer).forEach(key => {
            project['customer_' + key] = project.customer[key];
        })
        delete project.customer;
        return project;
    })
})