Merge pull request #19 from coderhaoxin/master

Update README.md
Quote column name to avoid issue when it same as SQL reserved words
Convert string to int automatically when query and update
Postgresql Dialet: fix primary tag for int types

There is not `sehrial`type in postgresql
Merge pull request #22 from siesta/master

Postgresql Dialect: fix primary tag for int types
Add test for float64 precision
Remove unnecessary output in tests
Add scripts to test all dialects
Refactor isBlank method
Test use int as primary key
Use method DB() to get database connection handle
Remove method SetPool() in favour of sql package's builtin method, Use
it like this `db.DB().SetMaxIdleConns(10)`

So gorm don't need to care about compatibility problems, and you could
use latest `database/sql` features from latest releases without waiting gorm's support
Fix postgres primary key sql tag