Update ttl dynamic

[kenshin]

When a request hit in cache. The ttl of this record is a static value configured at conf file. This is an incomplete implementation, the ttl should be update dynamic.

[Robert Šefr]

Are you up to this any time soon? @kenshinx ? Would really appreciate this one.

[kenshin]

@robcza ,I will try to update this as soon as possible.
However, i am worry i can't give you an specific date now, a plenty of heavy work recently.