Add notes on maintaining Docker based instances

[kobeBigs]

Added instructions on how to;

1. check running processes,
2. restart processes/containers
3. check and flush redis
4. change number of workers

[justinclift]

This seems like it would be useful, though it'd need a bit of updating to match the current commands. 😄

[kobeBigs]

This seems like it would be useful, though it'd need a bit of updating to match the current commands. 😄

@justinclift current commands? 😄 let me look into that

[justinclift]

Yeah, things like:

• Use docker compose (ie docker version 2 syntax) rather than docker-compose (docker version 1 syntax).

• Celery was replaced with RQ, so would need updating to match

• For the command to access PG, it's probably better to use the compose command instead:

  $ docker compose exec -u postgres postgres psql
  

Note that I'm kind of expecting the content of this page would have changed a bit since the PR was created. If so, then this PR would need updating to be based upon the current contents of the page (etc). Hopefully that makes sense. 😄

[kobeBigs]

@justinclift you are right. I will bring in the changes in master, try out the changes and revise.
Also, for the sake of folks still using Celery and docker-compose, I will bring in the current commands instead of replacing. What do you think?

[justinclift]

Good point. Those commands are likely still useful for people running older Redash releases. 😄