Add instructions for PostgreSQL setup.

README.md

@@ -2,7 +2,23 @@
 
 OpenDTU logger connects to the OpenDTU livedata websocket and captures metrics.
 These metrics are inserted into a PostgreSQL database.
-Optionally, TimescaleDB can be used for better performance.
+Optionally, TimescaleDB can be used.
+
+## PostgreSQL setup
+
+```sql
+CREATE DATABASE opendtu_logger;
+CREATE USER opendtu_logger WITH password 'SECRET';
+GRANT ALL privileges ON DATABASE opendtu_logger TO opendtu_logger;
+GRANT ALL ON SCHEMA public TO opendtu_logger;
+```
+
+Optional: enable TimescaleDB extension
+
+```sql
+\c opendtu_logger
+CREATE EXTENSION OF NOT EXISTS timescaledb;
+```
 
 ## Environment variables