To ditch = to leave behind, to throw away, to get rid of. Some examples: You should ditch that meeting and go to the movies instead. She ditched her boyfriend. He was a jerk. Let's ditch this town and go up North. You should ditch that diet. It's not good for your health.

Ditching in this sentence means getting rid of or eliminating the job/position. The word is frequently used to mean to stop something or get rid of something. Example: The schools are ditching standardized tests because they think they are unfair to some students. Or, We started a new customer service policy at the company, but we ditched it when customers complained. The idea of "ditching" may be that to thrown something into a ditch (a hole or pit in the ground) is a way of getting rid of it. "Ditching" is also used about getting away from somebody you don't want to spend time with. Example: Susie and Sally got tired of Betsy complaining that there were no cute guys at the bar, so they ditched her and went to another bar without her.

To ditch is used often in American English, to mean disregard "i ditched my boyfriend last night" for example, meaning, I broke up with him.

In this specific context, it means to fire the editor. It can have other meaning such as leave behind, throw away or jump out of a plane that may crash. But here, it means to fire.