Fleshing out the README

Author: futurechimp

README.md

@@ -1,3 +1,37 @@
 ## The Nym Privacy Platform
 
-It's Nym!
+This repository contains the full Nym platform, written in Rust.
+
+The platform is composed of multiple Rust crates. Top-level crates include:
+
+* client - an executable crate which you can use for interacting with Nym nodes
+* mixnode - an executable mixnode crate
+* sfw-provider - an executable store-and-forward provider crate. The provider acts sort of like a mailbox for mixnet messages.
+
+### Building
+
+#### Prerequisites
+
+* Rust 1.39 or later. Stable works.
+* The `nym` platform repo (this one).
+* Checkout the [Sphinx]() repo beside the `nym` repo.
+
+Your directory structure should look like this:
+
+```
+tree -L 1
+├── nym
+│   ├── client
+│   ├── mixnode
+│   ├── README.md
+│   └── sfw-provider
+├── sphinx
+```
+
+Entering each top-level crate (`client`, `mixnode` or `sfw-provider`) and doing a `cargo build` will build the software.
+
+As with any other Rust project, there are other ways to build:
+
+* `cargo build --release` will build an optimized release version for use in production
+* `cargo test` will run unit and integration tests for the crate (once)
+* `cargo watch -x test` will run tests whenever you change a file in the crate. Very handy in development.