Add Vuex to project and creat basic state properties

Pretty soon we're gonna add the month selector to our project, this is the thing at the top

right here where you can change the month.

You recall that in our app component just to look in our Vue devtools here for a second.

Our app component has the month and the year as fixed data and soon we want to change that

with this month selector up here, so it means we're gonna have some data sharing between

our different components, so this is a good