Avoid word repetition in README

Signed-off-by: Stephen Celis <stephen@stephencelis.com>
Quote table (query) names

This makes it possible to have tables named "table", tables with spaces,
quotation marks, etc.

Columns still aren't quoted because they're generic expressions, but
perhaps we can move towards something like:

    let id = Expression<Int>("id")
    // equivalent to `Expression<Int>(literal: quote(identifier: "id"))`

    users[id] // "users"."id"

Signed-off-by: Stephen Celis <stephen@stephencelis.com>