fix for "Contrib is not a class"
load tdiary/extensions explicitly (to load tdiary/extensions/core)

this fixes 404 error for tdiary-core's asset
Merge pull request #77 from minimum2scp/fix/contrib-is-not-a-class

fix for "Contrib is not a class"
Merge pull request #78 from minimum2scp/fix/load-extensions

tdiary-core のアセットが見えない(404 not found)問題を修正しました