Add toast for error messages, fix #16

src/lib/errorToast.ts

@@ -0,0 +1,8 @@
+import errorIcon from '$lib/assets/error-warning-fill.svg';
+import { toast } from '@zerodevx/svelte-toast';
+
+export function errorToast(message: string): number {
+  return toast.push(`<img src="${errorIcon}" />${message}`, {
+    classes: ['error']
+  });
+}