Automatic update of priority of table rows on new entries

I need to create a table of entries with list of people for webpage, where each row corresponding to one person. Each one needs to be given a priority number let us say 1 to 50 i.e., each person will have a priority number. One entry per row is dedicated for this. If a new person is added to the table row and given a priority number 3, all the other persons with priority from 3 to 50 should automatically change to 4 to 51 as new person’s priority is above all these. Please help me with the code for this.

I have no clue on what to do.