ASP.NET 5 is a new open-source, cross-platform, high performance and lightweight framework for building Web Applications using .NET.
Visual Studio Code is a cross-platform code editor refined and optimized for building modern web and cloud applications.
Yeoman is a scaffolding platform built on top of Node.js that allows you to build template-based generators for projects or code files. generator-aspnet is a yeoman generator that allows you to scaffold ASP.NET 5 applications.
OmniSharp is a set of tooling, editor integrations and libraries for developing in .NET. OmniSharp works with a number of editors including Atom, Brackets, Emacs, Sublime Text and Vim.