M1 JS Party - Add callouts for Ruby/JS differences

[hfaerber]

In M2 we identified differences between Ruby and JS that created stumbling blocks for students. We should call these out directly in the M1 JS Party exercises.

• Invoking a function in JS requires ()
• JS can use bracket or dot notation to access data in an object (hash)
• In Ruby they can only access a data set within a method if they pass it as an argument. JS can access global variables.