Add test for palindrome()

src/algorithms/string/palindrome/__true__/palindrome.test.js

@@ -0,0 +1,8 @@
+import palindrome from '../palindrome';
+
+describe('palindrome', () => {
+  it('should return true if word is a palindrome', () => {
+    expect(palindrome('racecar').toBe(true);
+    expect(palindrome('car').toBe(false);
+  }
+}