getting schema names

[ofajardo]

hi

I am puzzled about the behavior of get_schema_names in dialect.py. I was expecting it to retrieve all the schemas/databases in the system but instead of that only retrieves your username. What is the intention or usefulness of doing that?
Because I am connecting teradata to Apache superset, I needed that get_schema_names gives back the databases/schemas for SQL Lab to display them. I changed the function to look at DBC.Databases2V and it works like a charm.
If there is interest I can submit a PR.

thanks

[sandan]

A PR would be appreciated! I think there was confusion over which schemas to return.

[ofajardo]

PR submitted (#83)
The tests do not look straightforward, I commented that point in the PR.