Found the answer:
GRANT ALL PRIVILEGES ON SCHEMA mediawiki TO foouser;
On Wed, Jun 14, 2017 at 2:56 PM, Jean Valjean <jeanvaljean2718(a)gmail.com>
wrote:
I'm getting this error when I try to install
MediaWiki:
Tables creation failed. Make sure that the user "foouser" can write to the
schema "mediawiki".
What command should I run in psql to set up foouser so that it can write
to that schema?