fix wrong end times (duration instead of target).. how long has this been bugged?

back/tasks.py

@@ -165,7 +165,7 @@ def crop_video(in_fname,start_time,end_time,censuras,out_fname):
 
     process += [
                 '-ss', str(start_time),
-                '-t', str(end_time),
+                '-to', str(end_time),
                 '-c:v', 'copy',
                 '-movflags', '+faststart',
                 '-f', 'mp4', out_fname