Editor
noun
A knit someone is one who knits words together and makes them better. This someone is an editor.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
こちらの雑誌の編者を務めてくれた丸山君です。
This is Mr. Maruyama, who worked as the editor for this magazine.