Ruby prepending static string to a random string?

I figured out how to generate random strings a certain amount of times per line. Now, I'm trying to figure out how to add a fixed, static string to the prefix of all the randomly generated strings.

for example, if this code spits out gCOABGSS as a random string, I want to modify the script so it adds for example HEY-NOW to each of the outputs, resulting in HEY-NOWgCOABGSS

def generate_code(number)
  charset = Array('A'..'Z') + Array('a'..'z')
  Array.new(number) { charset.sample }.join
end


5.times { puts generate_code(8) }

How to go about this?