[feat : Issue #433 ] Added github-edit-link to sidebar

This link will direct anyone who wants to edit this page directly to the Github path which contains the file.

CHANGELOG :
1. Added the [GitHub Metadata] (http://jekyll.github.io/github-metadata/) plugin to Gemfile and Plugins
2. Added the link to the sidebar for license pages.

Github issue #433

Gemfile

@@ -8,6 +8,8 @@ versions = JSON.parse(open('https://pages.github.com/versions.json').read)
 
 gem 'github-pages', versions['github-pages']
 
+gem "jekyll-github-metadata"
+
 group :development do
   gem 'colored'
   gem 'fuzzy_match'

_config.yml

@@ -40,6 +40,8 @@ plugins:
   - jekyll-redirect-from
   - jekyll-seo-tag
   - jekyll-coffeescript
+  - jekyll-github-metadata
+
 
 sass:
     style: :compressed

_includes/sidebar.html

@@ -1,5 +1,7 @@
 <div class="sidebar">
 
+  {% github_edit_link "Help improve this page" %}
+
   <a href="#" data-clipboard-target="#license-text" data-proofer-ignore="true" class="js-clipboard-button button">Copy license text to clipboard</a>
 
   <div class="how-to-apply">