update docs

Author: aadrian

README.md

@@ -1,4 +1,4 @@
-gitbucket-explorer-plugin
+gitbucket-explorer-plugin [![Gitter](https://img.shields.io/gitter/room/gitbucket/gitbucket.js.svg?style=flat-square)](https://gitter.im/gitbucket/gitbucket) [![Travis](https://img.shields.io/travis/gitbucket/gitbucket-explorer-plugin.svg?style=flat-square)](https://travis-ci.org/gitbucket/gitbucket-explorer-plugin)
 ===
 
 This plugin provides an explorer like file tree for GIT repositories with [GitBucket](https://github.com/gitbucket/gitbucket).
@@ -10,6 +10,7 @@ Version
 
 Plugin version|GitBucket version
 :---|:---
+5.0|4.21.x+  |  
 4.0|4.16+
 3.x|4.11+
 2.0.0| 4.10+
@@ -30,12 +31,15 @@ Building
 Pre-requisites are Node, NPM, SBT, and Java 8.
  - Run `npm install` to install all node dependencies.
  - Run `npm run-script release` to create a **complete** release (this will call SBT too).
-  
+
 See `package.json` for more details.
- 
+
 Releases
 ---
 
+### 5.0.0 - 29 Jan 2018
+- Bump to GitBucket 4.21.2
+
 ### 4.0.0 - 5 Sept 2017
 - Bump to GitBucket 4.16
 
@@ -66,4 +70,4 @@ Releases
 Credits
 ---
 
-This plug-in was developed by [@tomoki1207](https://github.com/tomoki1207). 
+This plug-in was developed by [@tomoki1207](https://github.com/tomoki1207).