Add PostgreSQL schema functions

[ghost]

No description provided.

[elhigu]

Hi, thanks for PR. Are these functions already implemented? Is there any related issues?

[ghost]

Yes these functions are already implemented for PostgreSQL:
https://github.com/tgriesser/knex/blob/master/src/dialects/postgres/schema/compiler.js#L67

No related issues that I'm aware of. This is the original PR when the schema support was added:
knex/knex#518

[elhigu]

@jamarzka Thanks for the reference to PR.

I just looked into it and didn't see any tests for createSchemaIfNotExists, dropSchemaIfExists, createSchema, dropSchema so I'd rather not make them official features until there are some tests made written for them. These are so simple queries, that I'm fine with plain unit tests.

[rluvaton]

The website repo has been moved inside the https://github.com/knex/knex repo. Please open a PR there instead: (the website will be under the docs folder)