Query optimization assistant Joe now supports hypothetical indexes

Joe, a chatops bot that allows troubleshooting optimizing SQL performance
using fast thin clones of full-size databases (cloning of 10 TiB takes only
a couple of seconds), updated to version 0.6.0
https://postgres.ai/blog/joe-0.6/.

Two new commands were added:
- "hypo" to manage hypothetical indexes. The command allows performing
HypoPG functions such as creation, deleting and listing hypothetical
indexes, as well as estimating the index size.
In addition, it checks if the hypopg extension exists and automatically
runs the command CREATE EXTENSION hypopg; Moreover, if any hypothetical
index is present in the query plan, you will see two versions of the plan,
with and without HypoPG involved.
- "plan" to get a query plan without execution. The command knows about
hypothetical indexes as well.

See the full list of commands: https://postgres.ai/docs/joe-bot/usage

Links:
- The blog post about Joe 0.6.0: https://postgres.ai/blog/joe-0.6/
- Git repository and issue tracker: https://gitlab.com/postgres-ai/joe.
- Community Slack (English):
https://database-lab-team-slack-invite.herokuapp.com/. After joining, the
live demo is available in the #joe-bot-demo channel:
https://database-lab-team.slack.com/archives/CTL5BB30R.
- Joe command list: https://postgres.ai/docs/joe-bot/usage
- Extended images with PostgreSQL:
https://hub.docker.com/r/postgresai/extended-postgres Includes HypoPG,
pg_hint_plan, more.
- Proposals to add more extensions are welcome in the Custom Images repo:
https://gitlab.com/postgres-ai/custom-images