feat(strings): add is palindrome example for C#

strings/README.md

@@ -3,3 +3,7 @@
 ### C or C++
 
 1. [Palindrome Check](c-or-cpp/palindrome.c)
+
+### C#
+Please use [.Net Finddle](https://dotnetfiddle.net/)
+1. [Palindrome Check](csharp/palindrome.cs)

strings/csharp/palindrome.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Linq;
+					
+public class Program
+{
+	public static void Main()
+	{
+		bool result = false;
+		result = IsPalindrome("abba");
+		Console.WriteLine(result);
+		result = IsPalindrome("abbccbba");
+		Console.WriteLine(result);
+	}
+	
+	private static bool IsPalindrome(string source) {
+		string reverse = new string(Enumerable.Range(1, source.Length).Select(i => source[source.Length - i]).ToArray());
+		return reverse == source;
+	}
+}