Writable File System

I am trying to change the /system/etc/hosts of the android file system on an emulator. I do the following in one Terminal:

ionic cordova emulate android

And this in the other:

./adb shell
mount -o rw,remount,rw /system

But now matter what variation of commands I use for trying to mount the file system,I get this:

mount: Read-only file system

Is there a way to create an emulator in Ionic with a writable file system?