C# to Ruby

Person.cs

public class Person
{
    // Field 
    public string name;

    // Constructor that takes no arguments. 
    public Person()
    {
        name = "unknown";
    }

    // Constructor that takes one argument. 
    public Person(string nm)
    {
        name = nm;
    }

    // Method 
    public void SetName(string newName)
    {
        name = newName;
    }
}

Person.rb

class Person
  attr_reader :name
  
  def initializer(nm = 'unknown')
    @name = nm
  end
  
  def set_name(new_name)
    @name = new_name
  end
end