add adding-group-members.mkd
add changing-a-group-name.mkd
add creating-a-group.mkd
add listing-group-member.mkd
add listing-groups.mkd
add buckets.mkd
add object-storages.mkd
add file-storages.mkd
Merge pull request #55 from naoki-akimoto/add_managing_groups

Add managing groups
Merge pull request #57 from naoki-akimoto/add_managing-data

Add managing data pages
Port english version of managing data page for REST.
Port english version of buckets page for REST.
Port english version of object storages page for REST.
Port english version of file storages page for REST.
Remove redundant empty lines.
Fix layout.
Merge pull request #58 from shinsuke-nara/data

Port english version of managing data section for REST
Proofreading "Getting Started" (en and ja)
Merge branch 'develop'
Port english version of creating data page for REST.