flowtyped everything, some functional, safety, and structural changes

services/Service.js

@@ -1,10 +1,12 @@
-const Logger = require('../logger')
+// @flow
+import { Logger } from '../logger'
+import { type AppContext } from '../Roleypoly'
 
-class Service {
-  constructor (ctx) {
+export default class Service {
+  ctx: AppContext
+  log: Logger
+  constructor (ctx: AppContext) {
     this.ctx = ctx
     this.log = new Logger(this.constructor.name)
   }
 }
-
-module.exports = Service