Add organization public view

added organization view, and the description column to be shown to everyone.
added rspec test for get show organization.
reordered the "show" routing so it won't interfere with new
added feature spec for organization view
fixed routing issue
string -> text
:text didn't need :limit.
so removed it.
rollbacked the DB and removed migration files to change the
description column type for table "organizations".
added description column with type text to organizations table.
fixed the format
横長になった行を短くね。
descriptionがないときは、空のまま表示する(何も表示しない)ようにした
changed the format since desciption/context nest was so deep.
changed file name to the corrent one.
fixed the indentation of %li.