房奴 fángnú mortgage slave

wher does the phrase originate from?
In Shenzhen, a southern city in China, it's always very costly for common workers to buy an apartment or a house. A 32 -year-old Shenzhener surnamed Zhou from Futian complained that over half of his monthly salary went to pay his mortgage. Zhou felt he had become oppressed like serfs who couldn't leave the land on which they worked. He was the first person to use 房奴(fángnú) mortgage slave to describe his miserable situation. Then 房奴(fángnú) mortgage slave became popular very soon.

What does it mean?
房奴(fángnú) mortgage slave is used to describe those people who have to pay significant portion of their monthly salary toward mortgage payment. In order to pay off the mortgage, they dare not easily change their jobs. They spend little money on entertainment, and cannot afford to travel, let alone enjoy life. Meanwhile, they worry about being sick and losing their jobs. They suffer a lot in order to buy their own apartments, and have to struggle in life.

How to use the phrase?
E.g. 他把自己描述为公寓的房奴。(Tā bă zìjĭ miáoshù wéi gōngyù de fángnú.) 
       He described himself as a mortgage slave to his apartment.