Update 'FusionAuth/README.md'

Extended document with postgreSQL user and database creation

FusionAuth/README.md

@@ -52,5 +52,15 @@ password_encryption = scram-sha-256   # md5 or scram-sha-256
 
 ```
 
+###### 
+Create Database and user in PostgreSQL
+```
+systemctl enable postgresql --now
+sudo -u postgres psql
 
+postgres=# create database fusionauth;
+postgres=# create user fusionauth with encrypted password 'your-supersecret-password';
+postgres=# alter database fusionauth owner to fusionauth;
+postgres=# \q
+```