Update README.md

Author: javierron

README.md

@@ -67,7 +67,7 @@ To pass the course, the student has to complete and pass between 3 and 5 tasks:
   * B: 5 completed tasks 
   * A: 5 completed tasks + active participation in all but one lectures
 * Active participation: attendance to all but one lectures, a traceable record of questions asked during lectures (through GitHub issues) and the answers you received to them.
-* Group work is encouraged (max 2 persons) but you cannot be with the same person for more than 2 individual tasks. You can work alone for one or at most two tasks.
+* Group work is encouraged (max 2 persons) but you cannot be with the same person for more than 2 individual tasks. As a general rule, you are not allowed to work alone.
 * A failed task requires to pass it again at the end of the course (repeat), based on the feedback from the failure. A task can only be repeated once.
 * If the whole course is failed, no grades are kept if the student registers again to the course the year after. 
 * After a proposal has been merged, the topic of that proposal cannot be changed.