add update table capacity module
refactor updater module and add OverloadReport cache
add fronted page for database capacity monitor module
fix serval bugs
simply comparetor's logic
Merge branch 'master' of https://github.com/dianping/cat
trigger refresh
move database update module to new package, add none-metric-type log error
refactore database capacity module
remove log for debug
Merge pull request #486 from leonindy/master

add table capacity module, including backend updater task and frontend page