I would like to add a column in a data frame when another column is increasing/decreasing or stays the same with:
 1 -> increasing, 0 -> same, -1 -> decreasing

So if `df['battery'] = [1,2,3,4,7,9,3,3,3,]` 
I would like state to be `df['state'] = [1,1,1,1,1,-1,0,0]`