Blog

Merge this PR only after merging <a href="https://github.com/fsmk/camp-web/pull/46">this (major change for js and css structure, fix for all js issue #46)</a>

Full implementation of Blog slider on home page.
You can add blogs from active admin.

Here blog model is only for adding some basic contents from students who wrote blog about summer camp  last time. We will show its highlights on our home page as slider. Fix for issue #47