Add user creation instructions to Postgres destination

docs/integrations/destinations/postgres.md

@@ -9,10 +9,6 @@
 | Incremental - Deduped History | Yes |  |
 | Namespaces | Yes |  |
 
-## Overview
-
-This Postgres destination is based on the [Singer Postgres Target](https://github.com/datamill-co/target-postgres).
-
 #### Output Schema
 
 Each stream will be output into its own table in Postgres. Each table will contain 3 columns:
@@ -39,7 +35,19 @@ Make sure your Postgres database can be accessed by Airbyte. If your database is
 
 #### **Permissions**
 
-You need a Postgres user that can create tables and write rows. We highly recommend creating an Airbyte-specific user for this purpose.
+You need a Postgres user with the following permissions: 
+
+* can create tables and write rows. 
+* can create schemas e.g: 
+
+You can create such a user by runnig: 
+
+```
+CREATE USER airbyte_user PASSWORD <password>;
+GRANT CREATE, TEMPORARY ON DATABASE <database> TO airbyte_user;
+```
+
+You can also use a pre-existing user but we highly recommend creating a dedicated user for Airbyte.
 
 #### Target Database
 
@@ -55,7 +63,6 @@ You should now have all the requirements needed to configure Postgres as a desti
 * **Password**
 * **Default Schema Name**
 * **Database**
-* This database needs to exist within the schema provided.
 
 ## Naming Conventions