tip.rb

# 1. Define alphabet array
# 2. Split string into array of letters
# 3. Iterate over letters array
# For each letter
# 4. Shift letter three letter behind in the alphabet
# 4.1 Identify the letter index in the alphabet
# 4.2 Subtract 3 from index
# 4.3 Access new alphabet letter
# 6. Join shifted letters array into string

# puts encrypt("THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG") == "QEB NRFZH YOLTK CLU GRJMP LSBO QEB IXWV ALD"