Add a description of how the reference is published

This adds a description of how the reference gets published.

Closes #38

Author: ehuss

README.md

@@ -1,7 +1,19 @@
 # The Rust Language Reference
 
-This document is the primary reference for the Rust programming
-language.
+This document is the primary reference for the Rust programming language.
+
+## How is this published?
+
+The process for getting the reference content into a [Rust release](https://doc.rust-lang.org/reference/#rust-releases) and on the website is:
+
+1. Changes are merged to this repository.
+2. [Triagebot](https://forge.rust-lang.org/triagebot/doc-updates.html) will automatically synchronize this repository to [rust-lang/rust]. This happens every other week. The reference is tracked in [rust-lang/rust] as a [submodule](https://github.com/rust-lang/rust/tree/master/src/doc).
+    - If more frequent updates are desired, the bot can be poked via Zulip to do a sync immediately.
+    - This will open a PR on [rust-lang/rust] which needs to be merged, and that can take up to several days.
+3. At midnight UTC, whatever is on the default branch of [rust-lang/rust] will be a part of that nightly release, and will be published after a few hours to <https://doc.rust-lang.org/nightly/reference/>.
+4. Following Rust's [release process](https://doc.rust-lang.org/book/appendix-07-nightly-rust.html), every 6 weeks, nightly will be promoted to beta (<https://doc.rust-lang.org/beta/reference/>), and then 6 weeks after that it will be promoted to stable (<https://doc.rust-lang.org/stable/reference/>).
+
+[rust-lang/rust]: https://github.com/rust-lang/rust/
 
 ## Dependencies