Add JUnit test files:
	new file:   test/container_with_most_water/SolutionTest.java
	new file:   test/longest_palindromic_substring/SolutionTest.java
	new file:   test/median_of_two_sorted_arrays/SolutionTest.java
	new file:   test/permutions/Tests.java
	new file:   test/string_to_integer/SolutioTest.java
	new file:   test/three_sum/SolutionTest.java
	new file:   test/zig_zag_conversion/SolutionTest.java