• Do only one thing
• Non breaking API changes
• Tested

What did this pull request do?

create view #4966

It's different from issue's suggestion.
I found the unimplemented CreateView function in Migrator,
then I implemented it.

About ViewOption:

• Query is a subquey
• If Replace is true, exec CREATE OR REPLACE. sqlite may not support this.
• If CheckOption is not empty, append to sql, e.g. WITH LOCAL CHECK OPTION

User Case Description

DB.Migrator().CreateView("users_pets", gorm.ViewOption{Query: DB.Model(&User{}).Select("users.id, users.name")})

CREATE VIEW `users_pets` AS SELECT users.id, users.name FROM `users`