module SomeModule
  def happy?
    puts 'yes'
  end
end

#  I can do this:
some_object.extend(SomeModule)
some_object.happy?   # -> 'yes'

# But I really need to give the class the method (not just instances)
# because I have a collection of hundreds of thousands of objects
# and need them all to have the method quickly.

# The problem is that I don't know the class that needs to include the
method
# until runtime!

# This won't work:

some_object.class.include(SomeModule)
# -> NoMethodError: private method `include' called for <SomeClass>

# What is the workaround to add a method to a class (known only at
runtime)?

Thanks