use `link_to` for link to public users page
use Time.at for create timestamp from unix timestamp

```
Time.new(1375950030) # => 1375950030-01-01 00:00:00 +0900
Time.at(1375950030)  # => 2013-08-08 17:20:30 +0900
```

This causes Mysql2::Error: Incorrect datetime value: '1375950030-12-31 15:00:00' for column 'viewed_on'
fix api#item_count test

api#item_count returns after stored item's count since `params[:since]`.
Member.authenticate returns Member object (or nil), not member_id.
upgrade to rails4 and bump all gems
restructured /config/*
update /public/*
add .keep
remove script/rails
add /bin/*
add README.rdoc
Rakefile not to need shebang
rackup `Rails.application` instead of `Fastladder::Application`
comment updated.
protect_from_forgery take "with" option
remove attr_accessible, use StrongParameters
support StrongParameters on members#create
remove "mass-assignment error" test
config.secret_token rename to config.secret_key_base on rails4

rake setup now generate Fastladder::Application.config.secret_key_base
fix route error: Invalid route name, already in use: 'subscribe'