Added toString for permissions

ref #6

src/models/entities/Permission.ts

@@ -36,4 +36,11 @@ export class Permission {
    */
   @Column({ type: 'varchar' })
   action: PermissionAction;
+
+  /**
+   * Turn this into a string for exporting (and jwts).
+   */
+  public toString(): string {
+    return this.target + ":" + this.action;
+  }
 }