Every Google Doc is actually a website.  More accurately it is a webapp.  That means that it is a webpage with the ability for data to be processed in the cloud.  That is how you and your friend can both be writing  in a doc, and how you can install plugins. We can us a little bit of a language from Google called apps script to run some code every time that  a device adds an entry into a Google Sheet. 

The example here shows a timer running in the background of a spreadsheet and adding an entry when the timer adds t to indicate that a car that a student built has tripped a sensor.  It is worth pointing out that we could have just used block code run on the circuit playground to gather time data from a specific point.  One added value of this implementation is that even if several students had timers that they each started, because the timing is being run on the cloud, there is a single viewpoint and control on the data.  That means one student cannot do any shenanigans with their controller (like waiting a moment before they press start) to get a lower time.

For more ways this could be used, because this is built into the cloud, you could improve automation by having your sensor to email students whenever something outside or inside a specific boundary occurs so that they can check their setup.   You could even have the data being analyzed realtime, with the spreadsheet noting when data was gathered that fit certain criteria.