System of Eden is my book! You can find it on Inkitt! only three chapters out though (I'm very busy, writing is hard)
Eden is the last city on earth after we humans almost killed each other off and needed stability. They created the city, and within it, factions. Azim, the ones who do the hard labor. Verdad, the law enforcement and court systems. Kurunar, the entertainment and common goods. And Urafiki, the government and education. You get chosen a spouse at age 18 based on who you've been around most in your life and personality, and choose your faction. From there, you get a job from that faction. There is another option for a job, joining the secret military of Eden and keeping those who have committed horrible crimes (?) out of the city, for they ruined the haven that is Eden.
I thought this up at the thought of years from now, someone finding just a little bit of the story of the Garden of Eden, and becoming obsessed with it. Hope you all enjoy!