Update README

添加目录项

Author: tokers

README.md

@@ -1 +1,18 @@
 ## Learning lua-nginx-module
+
+### Table of Contents
+
+- phase
+  - [init_by_lua](chapters/001-ngx_lua_init_by_lua.md)
+  - init_worker_by_lua
+  - [rewrite_by_lua](chapters/003-ngx_lua_rewrite_by_lua.md)
+  - access_by_lua
+  - content_by_lua
+  - filter_by_lua
+  - log_by_lua
+
+- api
+  - ngx.ctx
+  - ngx.sleep
+  - ngx.var.VARIABLES
+  - others