adapt form's submit button text
 -- https://github.com/davidsulc/marionette-gentle-introduction/commit/43a0a4f8c491e1ae6f1ab65d20f51d4c9d867cde
implement filtering functionality -- https://github.com/davidsulc/marionette-gentle-introduction/commit/eb421e1464ed458c34c0424fb48e2f3411b52ecc