Clean up document and make config more generic

multidb-pg-pgbouncer/README.md

@@ -1,5 +1,9 @@
 # Multi Database PostgreSQL with PGBouncer
 
+This Compose project will let you run multiple database within one PostgreSQL container. It's based on (Cristian Angulo)[https://dev.to/nietzscheson/multiples-postgres-databases-in-one-service-with-docker-compose-4fdf]'s post on the subject.
+
+It also starts up a PGBouncer.
+
 ## ENV file
 Create a .env file with the following keys: 
 
@@ -26,3 +30,12 @@ Alternatively, bind mount a local directory for PostgreSQL to use.
 
 ## Logging
 This configuration will log to a mounted volume, using PostgreSQL logging, and not to Stderr / Docker logging as per the default image.
+
+## PGBouncer
+Add PGBouncer accounts with: 
+
+```bash
+./generate-userlist pgb_admin >> userlist.txt 
+```
+
+Update `pgbouncer.ini` adding the databases defined in POSTGRES_MULTIPLE_DATABASES to the `[databases]` section.