docs: add architecture document
docs: add architecture document

SomeKittens/angularjs-batarang,jbnicolai/batarang,seawenzhu/batarang,iegik/batarang,angular/batarang,vanessayuenn/batarang,erwinmombay/angularjs-batarang,erwinmombay/angularjs-batarang,DrewML/batarang,angular/batarang,jvilk/angularjs-batarang,SomeKittens/angularjs-batarang,vanessayuenn/batarang,seawenzhu/batarang,iegik/batarang,vanessayuenn/batarang,jvilk/angularjs-batarang,SomeKittens/angularjs-batarang,seawenzhu/batarang,DrewML/batarang,jbnicolai/batarang,hitesh97/batarang,hitesh97/batarang,DrewML/batarang,iegik/batarang,jbnicolai/batarang,hitesh97/batarang,angular/batarang,erwinmombay/angularjs-batarang,jvilk/angularjs-batarang