This plugin was referred to Octopress - Category List Plug-in.
cd plugins
wget https://raw.github.com/longkey1/octopress-category-list-plugin/master/category_list_tag.rb
or by git-submodule
cd /path/to/octopress
git submodule add git://github.com/longkey1/octopress-category-list-plugin.git plugins/category-list
example: category_list.html
vi /path/to/octopress/source/_includes/asides/category_list.html
+ <section>
+ <h1>Categories</h1>
+ <ul id="categories">
+ {% category_list %}
+ </ul>
+ </section>
vi /path/to/octopress/_config.yml
- default_asides: [asides/recent_posts.html, asides/github.html, asides/twitter.html, asides/delicious.html, asides/pinboard.html, asides/googleplus.html]
+ default_asides: [custom/asides/category_list.html, asides/recent_posts.html, asides/github.html, asides/twitter.html, asides/delicious.html, asides/pinboard.html, asides/googleplus.html]
cd /path/to/octopress
rake generate