Small Magento Module -- 2

basically... i am trying to create a magento module, which adds a custom attribute to product categories such as "visible on homepage", then im trying to make a template block that lists out all categories which have "visible on homepage" enabled. i got very close creating the module myself, but it doesn't seem to be saving the values for the custom attribute, and i can't get the frontend template block to work must work with magento 2.1.1