User drops csv file in browser, expects columns that can correspond to date and rainfall
Browser parses (using papa parse in service worker)
Browser offers column heading for matching date/rainfall
Browser checks data in correct format (e.g. regex rainfall to ensure only digits (or .), collate data that doesn't fit and ask how to handle (e.g. do they represent missing/null values)
Possibly present demo graph of a year, let user look at multiple graphs
Prompt for definitions (maybe start with just one)
Send to opencpu (possibly on google cloud run) to process using R script
present results in new graph, allow selection of year to show exact graph of that year (possibly colouring for start of season indicated)