Updated readme to include list of related projects (#794)

Author: ColeSeverson

README.md

@@ -111,6 +111,17 @@ There are a few different components to this repo:
 - [spirv-std](crates/spirv-std) for GPU intrinsics, types, and other library items used by GPU crates.
 - [spirv-builder](crates/spirv-builder) for a convenient way of building a GPU crate in a CPU build.rs file.
 
+## Related Projects
+Historical and other related projects for compiling Rust code to GPUs.
+- 2016: [glassful](https://github.com/kmcallister/glassful) Compiles a subset of Rust to GLSL.
+- 2017: [inspirv-rust](https://github.com/msiglreith/inspirv-rust) Experimental Rust to SPIR-V compiler.
+- 2018: [nvptx](https://github.com/japaric-archived/nvptx) Rust to PTX compiler.
+- 2019: [ocl](https://github.com/cogciprocate/ocl/) Pure OpenCl bindings and interfaces for Rust.
+- 2020: [accel](https://github.com/termoshtt/accel) GPGPU library for Rust.
+- 2020: [rlsl](https://github.com/MaikKlein/rlsl) Predeccesor to rust_gpu, Rust to SPIR-V compiler.
+- 2021: [emu](https://github.com/calebwin/emu) GPGPU library for Rust focusing on portability, modularity, and performance. 
+- Ongoing: [RustaCuda](https://github.com/bheisler/RustaCUDA) High-level interface for the NVIDIA CUDA API in Rust. 
+
 ## Contributing
 
 [![Contributor Covenant](https://img.shields.io/badge/contributor%20covenant-v2.0-ff69b4.svg)](CODE_OF_CONDUCT.md)