big_course.rb

Course.transaction do
  c = Course.create! name: "Big Course"
  c.offer

  s1 = c.course_sections.create! name: "Section 1"
  s2 = c.course_sections.create! name: "Section 2"

  500.times { |i|
    puts "creating user #{i+1}"
    u = User.create! name: ("Student %03d" % (i+1))
    e = c.enroll_user u, "StudentEnrollment", section: (i % 2).zero? ? s1 : s2
    e.accept
  }
end