feat: Add Ruby code - chapter "Hashing" (#1276)

* feat: add ruby code - chapter hashing

* feat: add ruby code blocks - chapter hashing

* fix: comments

codes/ruby/chapter_hashing/simple_hash.rb

@@ -0,0 +1,62 @@
+=begin
+File: simple_hash.rb
+Created Time: 2024-04-14
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+### 加法哈希 ###
+def add_hash(key)
+  hash = 0
+  modulus = 1_000_000_007
+
+  key.each_char { |c| hash += c.ord }
+
+  hash % modulus
+end
+
+### 乘法哈希 ###
+def mul_hash(key)
+  hash = 0
+  modulus = 1_000_000_007
+
+  key.each_char { |c| hash = 31 * hash + c.ord }
+
+  hash % modulus
+end
+
+### 异或哈希 ###
+def xor_hash(key)
+  hash = 0
+  modulus = 1_000_000_007
+
+  key.each_char { |c| hash ^= c.ord }
+
+  hash % modulus
+end
+
+### 旋转哈希 ###
+def rot_hash(key)
+  hash = 0
+  modulus = 1_000_000_007
+
+  key.each_char { |c| hash = (hash << 4) ^ (hash >> 28) ^ c.ord }
+
+  hash % modulus
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  key = "Hello 算法"
+
+  hash = add_hash(key)
+  puts "加法哈希值为 #{hash}"
+
+  hash = mul_hash(key)
+  puts "乘法哈希值为 #{hash}"
+
+  hash = xor_hash(key)
+  puts "异或哈希值为 #{hash}"
+
+  hash = rot_hash(key)
+  puts "旋转哈希值为 #{hash}"
+end