Remove constraint require

Rails.root/lib is in autoload paths, no need to require them.
Merge pull request #144 from peatio/remove-constraint-require

Remove constraint require
Preserve spaces around tags and text using trailing and leading whitespace for slim tag
Fix core team link

https://github.com/orgs/peatio/members does not exist.
Merge pull request #147 from peatio/fix-footer-links

Fix footer links
add timestamp to depth api response
Switch position of tickets and exit at top menu
add api_disabled field to members
toggle api access
change DatabaseCleaner strategy to deletion