Playing with the basic ceasar cipher

ceasar_cypher.rb

def create_ceasar_cipher(phrase, key)
	letters = phrase.scan(/./)
	new_phrase = []
	letters.each do |letter|
		num = letter.ord
		num += key
		new_letter = num.chr
		new_phrase << new_letter
	end 
	puts new_phrase.join("")
end  


def solve_ceasar_cipher(phrase, key)
	letters = phrase.scan(/./)
	new_phrase = []
	letters.each do |letter|
		num = letter.ord
		num -= key
		new_letter = num.chr
		new_phrase << new_letter
	end 
	return new_phrase.join("");
end 


def break_ceasar_cipher 
	i = 0 
	num = -50
	all_solutions = []
	while num < 0 do 
		solution = solve_ceasar_cipher("'5p\"?<<p?%\"p?'>p3\"$) ?", num)
		all_solutions << solution
		num +=1
	end 
	while i < all_solutions.length do 
		possible_solution = all_solutions[i].downcase
		if contains_english(possible_solution)
			puts possible_solution
		end 
		i += 1
	end 
end 

def contains_english(phrase)
	common_letter_combinations = ["the", "ee", "tt", "oo", "ss", "ll", "ff", "the", "he", "re", "an", "th", "er", "in", "ion", "and", "ing", "ent"]
	i = 0 

	while i < common_letter_combinations.length-1 do 
		i += 1 
		if phrase.include? common_letter_combinations[i]
			return true
		end 
	end 
end 
break_ceasar_cipher