Update github plugin.

* add dependencies.
* tuning output.

Signed-off-by: Eric Wang <skygragon@gmail.com>

Author: skygragon

github.js

@@ -1,15 +1,13 @@
 var path = require('path');
 var url = require('url');
 
-var GitHubApi = require('github');
-
 var h = require('../helper');
 var log = require('../log');
 var Plugin = require('../plugin');
 
 // [prerequisite]
 //
-// 1. create a new access token on your github repo setting. (TBD)
+// - create a new access token on your github repo setting. (TBD)
 //
 // [config]
 //
@@ -19,12 +17,9 @@ var Plugin = require('../plugin');
 //     "token": "<token created above>"
 //   }
 // }
-var plugin = new Plugin(100, 'github', '2017.08.09',
-    'Plugin to commit accepted code to your own github repo.');
-
-var github = new GitHubApi({
-  host: 'api.github.com'
-});
+var plugin = new Plugin(100, 'github', '2017.08.10',
+    'Plugin to commit accepted code to your own github repo.',
+    ['github']);
 
 var ctx = {};
 
@@ -38,32 +33,31 @@ plugin.submitProblem = function(problem, cb) {
   ctx.repo = parts.shift();
   ctx.path = parts.join('/');
 
+  var GitHubApi = require('github');
+  var github = new GitHubApi({host: 'api.github.com'});
   github.authenticate({type: 'token', token: this.config.token});
+
   plugin.next.submitProblem(problem, function(_e, results) {
-    if (_e || !results[0].ok) return cb(_e, results);
+    cb(_e, results);
+    if (_e || !results[0].ok) return;
 
     log.debug('running github.getContent: ' + filename);
     github.repos.getContent(ctx, function(e, res) {
       if (e && e.code !== 404) {
-        log.error('[github] failed: ' + e.message);
-        return cb(_e, results);
+        return log.info('  ' + h.prettyText(' ' + e.message, false));
       }
 
       ctx.message = 'update ' + filename;
       ctx.content = new Buffer(h.getFileData(problem.file)).toString('base64');
 
       var onFileDone = function(e, res) {
-        if (e) {
-          log.error('[github] failed: ' + e.message);
-          return cb(_e, results);
-        }
+        if (e)
+          return log.info('  ' + h.prettyText(' ' + e.message, false));
 
         log.debug(res.meta.status);
         log.debug('updated current file version = ' + res.data.content.sha);
         log.debug('updated current commit = ' + res.data.commit.sha);
-
-        log.info('[github] successfully committed to ' + plugin.config.repo);
-        return cb(_e, results);
+        log.info('  ' + h.prettyText(' Committed to ' + plugin.config.repo, true));
       };
 
       if (e) {