Fix Sqlite BLOB type.

[Hirtol]

Closes SeaQL/sea-orm#490

Not entirely sure why it was done with an alias, but by changing the ColumnType to binary the following schema (when used with sea-orm-cli):

CREATE TABLE "Books"
(
    id             INTEGER                                  NOT NULL PRIMARY KEY AUTOINCREMENT,
    title          TEXT                                     NOT NULL,
    hash           BLOB                                     NOT NULL UNIQUE,
)

Used to produce:

#[derive(Clone, Debug, PartialEq, DeriveEntityModel)]
#[sea_orm(table_name = "Books")]
pub struct Model {
    #[sea_orm(primary_key)]
    pub id: i32,
    pub title: String,
    #[sea_orm(column_type = "Custom(\"BLOB\".to_owned())")]
    pub hash: String,
}

And will now produce:

#[derive(Clone, Debug, PartialEq, DeriveEntityModel)]
#[sea_orm(table_name = "Books")]
pub struct Model {
    #[sea_orm(primary_key)]
    pub id: i32,
    pub title: String,
    pub hash: Vec<u8>,
}

[billy1624]

Thanks!! @Hirtol

[tyt2y3]

Thank you