added backup script

docker/Dockerfile.postgres

@@ -7,3 +7,5 @@ RUN apt-get update && apt-get install -y unzip curl && rm -rf /var/lib/apt/lists
 RUN curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
 RUN unzip -q awscliv2.zip
 RUN ./aws/install
+
+COPY ./backup_pg_to_s3.sh .

docker/backup_pg_to_s3.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+set -e
+set -x
+
+# filename with timestamp
+filename="postgres-$(date +%Y-%m-%d_%H-%M-%S).sql"
+
+# perform pg_dump
+pg_dump -U postgres postgres > /tmp/$filename
+
+# upload to s3
+aws s3 cp /tmp/$filename s3://$S3_BUCKET_NAME/$filename