add error notice

README.md

@@ -7,6 +7,9 @@ The algorithm reads student requests and generates a timetable for all requested
 The algorithm has been moved out of `tinker.py` into its own python script. Version 1 and 2 are removed and the script can be found in the `/scheduleGenerator` folder. The algorithm has come a long way; using real 2018 course selection data from my school, enabling me to better test the script. V3 has a entirely different approach from V1 and V2, that you can read about at the top of the function in [`generator.py`](/scheduleGenerator/generator.py). The function is broken up into 6 steps, each step is labeled within the function with a comment, giving a brief explination of what that step contributes to the algorithm.
 
 Here is the list of commands.
+
+Note: to show a basic error table, include `show_error` in your command args.
+
 1. Collect latest data from files and generate timetable
 ```
   $ ./tinker.py