Insert/Update for boolean fields fails in MSSQL

[srs]

When trying to insert or update a record in MSSQL using MSSQL dialect it fails. The reason is that BUN creates an SQL with TRUE or FALSE which is not supported in MSSQL. The recomended type for using boolean in MSSQL is a BIT-type.

Is it a way for this to work with current BUN version? I do not want to change the entity field to use a number instead of a boolean. It would be nice to let BUN do this work instead of customizing our domain objects to support MSSQL.

[srs]

I see that AppendBool is not implemented in a dialect, but just directly used. It would be good if AppendBool would be in the dialect interface so it can be implemented in MSSQL-dialect as a number.

Current implementation:

func AppendBool(b []byte, v bool) []byte {
	if v {
		return append(b, "TRUE"...)
	}
	return append(b, "FALSE"...)
}

[srs]

See #697 for pull request.