In this story, a character discovers anti gravity emitters, flies a shipping container into space and docks with space station.
Galactic Startup (2018), by Brian Whiting
In Galactic Startup, the opening novel in a series of the same name, a group of young adult friends promote their new spaceflight company and test their invention of an antigravity drive by flying a shipping container to the International Space Station.
Alex and his three friends drop out of college after discovering a revolutionary way to travel into space using a small amount of energy. Their world-changing technology is sought by the government, and they are forced to go into hiding while they perfect it. Their adventures into orbit and beyond become a global sensation. As they navigate fame, family and those who are determined to stop them, little do they know that their little startup could have galactic consequences once they discover a derelict spaceship.
— Goodreads: Galactic Startup
As of 2019, there are 3 novels in the Galactic Startup series: