update method CombinedConditionSql
clone callback when call Callback
change callback names
refact
rename couple of scope related methods
Add some documents
Format document
Fix comparing uncomparable type error
Add tests for updated_at will be updated when update value with Assign
Fixed double logging of UPDATE and DELETE commands.
Merge pull request #64 from fuzzac/master

Fixed double logging of UPDATE and DELETE commands.
Use the same database for Related
Merge pull request #1 from jinzhu/master

update from parent