_posts以下のファイルをIssue
Merge pull request #236 from jekyllrb-ja/create_posts_diff

_posts以下のファイルをIssue化
update structure.md
update sites.md
Merge pull request #244 from satoso/iss179

update sites.md
Merge pull request #243 from satoso/iss180

update structure.md
exclude diff directory from build
remove quote marks
Merge pull request #245 from melborne/exclude-diffs

exclude diff directory from build