Add method to close gorm db connection
When multiple databases have the same table name and column names, automigrate doesn't work
remove package dialect for easier contribution
Merge branch 'sunfmin-master'

Conflicts:
	main.go
Add method HasTable, HasColumn to dialect
Include table_schema when query from INFORMATION_SCHEMA for mysql
Fix invalid SQL issue
Merge branch 'master' of https://github.com/jinzhu/gorm