added gradient definitions

src/app/app.component.ts

@@ -1,4 +1,6 @@
 import { Component, OnInit, ChangeDetectorRef } from '@angular/core';
+
+import { Param } from './models/param.model';
 import { Config } from './models/config.model';
 
 @Component({
@@ -7,7 +9,17 @@ import { Config } from './models/config.model';
   styleUrls: ['./app.component.scss']
 })
 export class AppComponent {
-  public canvasConfig: Config|null;
+  public canvasConfig: Config;
+  public canvasParam: Param;
+
+  constructor() {
+    this.canvasParam = {
+      colors: {
+        start: '#cc0045',
+        end: '#0067cc'
+      }
+    };
+  }
 
   public updateCanvasConfig(config): void {
     this.canvasConfig = config;