Revert "【3】演習２"

This reverts commit af766d32e593a2fe70e5911f2bb8698d9671d7ac.
Revert "Add a full_title helper"

This reverts commit b68ef73e7e2f48bf5d8279c1b9aec9396b181434.
Revert "演習1"

This reverts commit 67ce58ae2b54aa3824850e6125c57b031cafd053.
Revert "Finish static pages"

This reverts commit 8826ba0e160820b216fa619d58d595b2cf6aebfd.
Revert "Add a StaticPages controller"

This reverts commit 293aa4a877d57715d43ff6515335276c4e9d0004.