Create structs from string instead of live database connection

[montanaflynn]

First off thanks for the great repo, I'm sure this would be of use to many people.

I wonder if it's possible to get the structs from a SQL definition instead of connecting to the database? I'm thinking it would accept the create table SQL either through a file, stdin or a flag. This would allow a nice web UI like https://mholt.github.io/json-to-go/