docs(readme): populate readme

README.md

@@ -1 +1,81 @@
 # Emacs Builds
+
+<p>
+  <a href="https://github.com/jimeh/emacs-builds/releases">
+    <img src="https://img.shields.io/github/v/tag/jimeh/emacs-builds?label=nightly" alt="GitHub tag (latest SemVer)">
+  </a>
+  <a href="https://github.com/jimeh/emacs-builds/issues">
+    <img src="https://img.shields.io/github/issues-raw/jimeh/emacs-builds.svg?style=flat&logo=github&logoColor=white"
+alt="GitHub issues">
+  </a>
+  <a href="https://github.com/jimeh/emacs-builds/pulls">
+    <img src="https://img.shields.io/github/issues-pr-raw/jimeh/emacs-builds.svg?style=flat&logo=github&logoColor=white" alt="GitHub pull requests">
+  </a>
+</p>
+
+Nightly binary builds of Emacs for macOS, with native-compilation enabled, as a
+completely self-contained Emacs.app application bundle.
+
+# Features
+
+- Self-contained Emacs.app application, with no external dependencies.
+- Native-compilation is enabled in nightly builds from the `master` branch of
+  Emacs, and should just work without the need to install GCC, libgccjit, or any
+  other dependencies.
+- Includes the [fix-window-role][] and [system-appearance][] patches from the
+  excellent [emacs-plus][] project.
+- Build are creation is transparent and public through the use of GitHub
+  Actions, allowing anyone to inspect git commit SHAs, full source code, and
+  exact commands used to produce a build. This is especially important right now
+  as builds are not yet signed and notarized.
+
+[fix-window-role]:
+  https://github.com/d12frosted/homebrew-emacs-plus/blob/master/patches/emacs-28/fix-window-role.patch
+[system-appearance]:
+  https://github.com/d12frosted/homebrew-emacs-plus/blob/master/patches/emacs-28/system-appearance.patch
+[emacs-plus]: https://github.com/d12frosted/homebrew-emacs-plus
+
+## Downloads
+
+See the [Releases][] page to download latest builds.
+
+[releases]: https://github.com/jimeh/emacs-builds/releases
+
+## Build Process
+
+Building Emacs is done using the [jimeh/build-emacs-for-macos][] build script,
+executed within a GitHub Actions workflow. Full build history is available
+[here][actions].
+
+[jimeh/build-emacs-for-macos]: https://github.com/jimeh/build-emacs-for-macos
+[actions]: https://github.com/jimeh/emacs-builds/actions
+
+Nightly builds are scheduled for 2:35 UTC, based on the latest commit from the
+`master` branch of the [emacs-mirror/emacs][] repository. This means a nightly
+build will only be produced if there have been new commits since the last
+nightly build.
+
+[emacs-mirror/emacs]: https://github.com/emacs-mirror/emacs
+
+## Untrusted Application
+
+Currently builds are not signed or notarized, meaning macOS cannot verify
+Emacs.app came from a trusted developer, and by default you are not even given
+the option to trust the app and open it anyway.
+
+Simplest way around this: Instead of double-clicking on Emacs.app in Finder,
+right-click (or control-click) on Emacs and select "Open". You will then be
+given the same warning as before, with a "Open" button now available to open the
+app anyway. After that you can open the application like normal without any
+warnings.
+
+## To-Do
+
+- [ ] Sign and notarize builds.
+- [ ] Builds for stable versions of Emacs.
+- [ ] Populate GitHub Release description with relevant info about the build,
+      including a link to the GitHub Actions workflow run that produced the
+      build.
+- [ ] (Eventually) support Apple Silicon mac builds when native-compilation
+      actually works on Apple Silicon.
+- [ ] (Eventually) support builds for Linux.