Add a basic README.md.

Cargo.toml

@@ -3,6 +3,7 @@ name = "wasm-singlepass-experiment"
 version = "0.0.0"
 authors = ["Dan Gohman <sunfish@mozilla.com>"]
 license = "Apache-2.0 WITH LLVM-exception"
+readme = "README.md"
 publish = false
 
 [dependencies]

README.md

@@ -0,0 +1,16 @@
+# Wasm Singlepass Experiment
+
+This is an early-stage experimental project to build a single-pass
+wasm-function-to-machine-code translator.
+
+It's currently built with [dynasm](https://crates.io/crates/dynasm) and
+targets x86-64, however the function\_body.rs/backend.rs split is likely
+to evolve towards a configuration point allowing other targets or even
+other assemblers to be supported.
+
+It's a very early stage project, and a good one for learning how
+WebAssembly works at a low level, for learning assembly programming, or
+both! And we're happy to mentor. So welcome, and check out the
+[issue tracker] to see what's happening and how to get involved!
+
+[issue tracker]: https://github.com/sunfishcode/wasm-singlepass-experiment/issues