Thanks for pointing this out @Brad, your feedback is super helpful 
You can look for some updated info on installing and configuring Postgres in the next Beta release. As for seeing slightly different output from the mix phx new pento --live command–that would likely be due to your using a different Phoenix version than the one with which the Pento app is generated. Some added text to clarify that this might be the case for readers will probably help here. Look for that in the upcoming release as well!