So, what is docker and Postgres ?

Docker : Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers.

PostgreSQL:  PostgreSQL is a free and open-source relational database management system emphasizing extensibility and SQL compliance. 

1. Run Postgres in docker 

docker run --name some-postgres -p 5432:5432 -e POSTGRES_PASSWORD=mysecretpassword -d postgres

2. Check docker container status

docker ps 

Now you can see your docker container id like this :

lets go inside docker as a bash shell

docker exec -it <CONTAINER ID> bash

docker exec -it d909cca76479 bash

3. Connect to Postgres and create database with user

Lets first, create database  

create database newdb;

create user with password

create user newuser with encrypted password 'mynewpassword';

add user to database 

 grant all privileges on database newdb to newuser;

4. Backup and Restore are same you just need to change  "  > " direction for backup and " < " for restore. 

pg_dump -C -h [Hostname] -d [dbname] -p [port] -U [username] -W > backup.sql

OR

Restore your databases

cat backup.sql | docker exec -i <CONTAINER ID> psql -U newuser newdb

That's how simple it is to manage postgres in docker!