This is an update of https://gist.github.com/svanzoest/4028058 for Gitlab 5.2.0.

create_user.rake

# gitlab 5.2.0 create user
# rake create_user["john@doe.com","johndoe","John Doe"] RAILS_ENV=production
desc "Create new user"
task :create_user, [:email, :username, :name] => :environment do |t, args|
  puts "creating user '" + args.username + "' ('" + args.name + "') with email '" + args.email + "'"
  @user = User.new({ email: args.email, name: args.name, username: args.username, force_random_password: true, projects_limit: 10 }, as: :admin)

  if @user.save
    puts "success"
  else
    puts "failed"
  end
end