Start using sinatra & ruby for backend

Signed-off-by: Syed Daanish <me@syedm.dev>

event_bus.rb

@@ -0,0 +1,12 @@
+# Event bus
+module EventBus
+  @events = {}
+
+  def self.on(event, &callback)
+    @events[event] = callback
+  end
+
+  def self.get(event, *args)
+    @events[event]&.call(*args)
+  end
+end