Creating an external plugin for TinyMCE

Guys, I am following this link and the following code

[ModuleDependency(typeof(TinyMceInitialization))]
public class CustomizedTinyMceInitialization : IConfigurableModule
{
    public void Initialize(InitializationEngine context)
    {
    }
    public void Uninitialize(InitializationEngine context)
    {
    }
    public void ConfigureContainer(ServiceConfigurationContext context)
    {
        context.Services.Configure<TinyMceConfiguration>(config =>
        {
            config.Default()
                .AddExternalPlugin("custom-plugin", "alloy/plugins/custom-plugin.js");
        });
    }
}

but I am strugling to understand what should be the structure within solution i.e. where should I put my custom-plugin.js? No matter where I place the custom-plugin.js, i always get 404 in console :(

My structure is as follows

• ClientResources
  • Scripts
    • plugins
      • custom-plugin.js

Any help will be appreciated.