For blog post on memoization and recursion

memoization.rb

# When this method is called on any class instance,
# the method will reconstruct the string every time. 

def user_full_name
  "#{first_name} #{last_name}"
end

# By memoizing the call, we store the string with the
# object that is the class instance. Below is a classic
# example of memoization in code:

def user_full_name
  @user_full_name ||= "#{first_name} #{last_name}"
end