Refactor project structure

backend/src/Model/Base64Message.ts

@@ -1,4 +1,4 @@
-import { Base64 } from 'js-base64'
+const Base64 = require('js-base64')
 
 export class Base64Message {
   private base64Message: string

backend/src/Model/Edge.ts

@@ -12,7 +12,7 @@ export class Edge<ViewModel> implements Hashable {
     this.name = name
   }
 
-  public edges() {
+  public edges(): Array<Edge<ViewModel>> {
     return this.target ? this.target.edgeArray : []
   }