feature(readme):update readme,add link to js & java file

Author: guocaoyi

README.md

@@ -4,7 +4,7 @@ Environment:
  Node:8.0+
  Java:1.8+
 
-Num | Problems | With in Language  
------------- | ------------- | ------------ 
-1 | Two Sum | [JS](/js/src/TowSum.js) [JAVA](/java/src/TowSum.java)
-2 | Add Tow Numbers | [JS](/js/src/AddTwoNumbers.js)
+Num | Problems | With in Language | Commons
+------------ | ------------ | ------------ | ------------
+1 | [Two Sum](/subject/001_050.md#1.-Two-Sum) | [JS](/js/src/TwoSum.js) [JAVA](/java/src/TwoSum.java) |
+2 | [Add Tow Numbers](/subject/001_050.md#2.-Add-Two-Numbers) | [JS](/js/src/AddTwoNumbers.js) | 

java/src/TowSum.java renamed to java/src/TwoSum.java

@@ -1,4 +1,4 @@
-1. Two Sum
+# 1. Two Sum
 
 Given an array of integers, return indices of the two numbers such that they add up to a specific target.You may assume that each input would have exactly one solution,and you may not use the same element twice.
 
@@ -12,7 +12,7 @@ return [0, 1].
 Slution:
 Test:
 
-2. Add Two Numbers
+# 2. Add Two Numbers
 
 You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.