Adds Dockerfile and initdb.sh

Dockerfile

@@ -0,0 +1,7 @@
+FROM postgres
+COPY ./initdb.sh:/docker-entrypoint-initdb.d/initdb.sh
+EXPOSE 5432
+VOLUME ["/var/lib/postgresql/data"]
+ENV POSTGRES_USER=$POSTGRES_USER
+ENV POSTGRES_PASSWORD=$POSTGRES_PASSWORD
+ENV POSTGRES_MULTIPLE_DATABASES=$POSTGRES_MULTIPLE_DATABASES

initdb.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+set -e
+set -u
+
+function create_user_and_database() {
+	local database=$1
+	echo "  Creating user and database '$database'"
+	psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" <<-EOSQL
+	    CREATE USER $database;
+	    CREATE DATABASE $database;
+	    GRANT ALL PRIVILEGES ON DATABASE $database TO $database;
+EOSQL
+}
+
+if [ -n "$POSTGRES_MULTIPLE_DATABASES" ]; then
+	echo "Multiple database creation requested: $POSTGRES_MULTIPLE_DATABASES"
+	for db in $(echo $POSTGRES_MULTIPLE_DATABASES | tr ',' ' '); do
+		create_user_and_database $db
+	done
+	echo "Multiple databases created"
+fi