It’s in the collection, The Early Asimov. Don’t spend a lot of money on it because you should be able to find a copy of this novella on it’s own around the internet somewhere.
After all the robot stories, we skip forward many years until humans have colonised lots of far flung systems.
Earth is overcrowded and under resourced so many people are wanting to go to the new frontiers, but the frontier has banned all immigration and won’t accept any more people from Earth.
But someone on Earth has a plan, the
Another good story.
Next up is The Caves of Steel
This is a full length novel version of 
