Define psql extra options

[fljdin]

A psql task should define some extra options to use with psql client

Examples:

• -At: no-align and tuples only
• -L or -o: output into log file
• -P: other printing options, in the style of \pset
• -v or --set: variable assignment like the \set meta-command

[fljdin]

PR #21 provides an alternative to some requested features

Example:

tasks:
  - id: 1
    type: psql
    name: No-align and tuples only (or other \pset options)
    command: SELECT 1 \g (format=unaligned tuples_only)

  - id: 2
    type: psql
    name: Expanded printing option
    command: SELECT 1 \gx

  - id: 3
    type: psql
    name: output into log file
    command: SELECT 1 \g output.txt