add support for em_mysql2 adapter in AR rake tasks
Merge pull request #1370 from spariev/patch-1

add support for em_mysql2 adapter in AR rake tasks
Fix prioritized routes doesn't work in rbx.
Remove keys.
Merge pull request #1371 from namusyaka/fix-priority-for-rbx

Fix prioritized routes doesn't work in rbx. Closes #1362