Package fails to inference type of column for PostgreSQL data_types

DBT's data_type can have more broader set of types that are currently I see in package's source. The type can be any of supported in underlying database. For exple, PostgreSQL **varchar** type:

```
Error: invalid operation: Error while calling method: Python error: RuntimeError: Unknown column type of volumes.id: varchar(255)
```

Package version: 0.6.0

No source file, test, or entry point is named. Start by reproducing the PostgreSQL varchar(255) failure against package version 0.6.0, then trace the type-inference path; done means supported PostgreSQL data types are recognized instead of producing an unknown column type error.

Written by the indexing model from the issue text.