chore: bind-mount postgres/redis data dirs, update docs for pocketveto.org

- docker-compose.yml: replace named volumes with ./postgres/data and ./redis/data bind mounts
- .gitignore: exclude postgres/ and redis/ data directories
- DEPLOYING.md: update clone URL to public PocketVeto repo
- UPDATING.md: fix paths (~/pocketveto), clone URL, webhook IDs

Authored by: Jack Levy

DEPLOYING.md

@@ -27,9 +27,8 @@ Google Trends (`pytrends`) needs no key.
 ## 1. Get the code
 
 ```bash
-git clone https://git.jackhlevy.com/jack/civicstack.git
-# (Replace with your own fork URL or download a release from pocketveto.org)
-cd civicstack
+git clone https://git.jackhlevy.com/jack/PocketVeto.git pocketveto
+cd pocketveto
 ```
 
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