grouping.rb

list = [
  {
    id: 1,
    name: 'ze',
    age: 12,
    app_id: 1,
    url: 'www.1.com'
  },
  {
    id: 1,
    name: 'ze',
    age: 12,
    app_id: 2,
    url: 'www.2.com'
  },
  {
    id: 1,
    name: 'ze',
    age: 12,
    app_id: 3,
    url: 'www.3.com'
  },
  {
    id: 2,
    name: 'Marcos',
    age: 14,
    app_id: 1,
    url: 'www.1.com'
  }
]

list = list.each_with_object({}) do |user, grouped_list|
  id = user[:id]

  if grouped_list[id].nil?
    grouped_list[id] = {
      id: id,
      name: user[:name],
      age: user[:age],
      applications: [{ id: user[:app_id], url: user[:url] }]
    }
  else
    grouped_list[id][:applications] << { id: user[:app_id], url: user[:url] }
  end
end