Auto migration should support all dialect native type

Now, during auto migration, only part of dialect native type have been checked to be `field.Other` type, like the newly added MySQL spatial types in `0.7.0`. Though a lot of dialect native type haven't been checked, and the auto migration process will report:
```
failed creating schema resources: sql/schema: invalid type "xxx" for column yyy
```
like the postgres native `tstzrange` or `array` type.

I don't know is there any side effect to check all unsupported dialect native type to be `field.Other` type?

Or the dialect native column type information should included in the generated code? like the generated `migrate/schema.go` file should contain infomation about the unsupported dialect native column type?