Start sketching out an actual contributor's guide.

- Add AUTHORS file
- Update README to match site docs

README.md

@@ -1,21 +1,27 @@
-Wren is a *small, clean, fast, class-based scripting language.* Think Smalltalk
-in a Lua-sized package.
+## Wren is a small, fast, class-based concurrent scripting language
+
+Think Smalltalk in a Lua-sized package with a dash of Erlang and wrapped up in
+a familiar, modern [syntax][].
 
 ```dart
 IO.print("Hello, world!")
 
 class Wren {
-  adjectives { ["small", "clean", "fast"] }
-  languageType { "scripting" }
+  flyTo(city) {
+    IO.print("Flying to ", city)
+  }
 }
+
+var adjectives = new Fiber {
+  ["small", "clean", "fast"].map {|word| Fiber.yield(word) }
+}
+
+while (!adjectives.isDone) IO.print(adjectives.call)
 ```
 
- *  **Wren is small.** The codebase is under 4,000 semicolons which keeps the
-    language and libraries small enough to fit in your head. You can skim
-    [the whole thing][src] in one sitting.
-
- *  **Wren is clean.** The codebase is *small*, but not *dense*. It is readable
-    and [lovingly-commented][nan]. It's written in warning-free standard C99.
+ *  **Wren is small.** The codebase is about [5,000 lines][src]. You can
+    skim the whole thing in an afternoon. It's *small*, but not *dense*. It
+    is readable and [lovingly-commented][nan].
 
  *  **Wren is fast.** A fast single-pass compiler to tight bytecode, and a
     compact object representation help Wren [compete with other dynamic
@@ -25,12 +31,24 @@ class Wren {
     but many have unusual or non-existent object models. Wren places
     [classes][] front and center.
 
+ *  **Wren is concurrent.** Lightweight [fibers][] are core to the execution
+    model and let you organize your program into an army of communicating
+    coroutines.
+
  *  **Wren is a scripting language.** Wren is intended for embedding in
     applications. It has no dependencies, a small standard library,
-    and [an easy-to-use C API][embedding].
+    and [an easy-to-use C API][embedding]. It's written in warning-free
+    standard C99.
 
+If you like the sound of this, [give it a try][try]! Even better, you can
+[contribute to Wren itself][contribute].
+
+[syntax]: http://munificent.github.io/wren/syntax.html
 [src]: https://github.com/munificent/wren/tree/master/src
 [nan]: https://github.com/munificent/wren/blob/46c1ba92492e9257aba6418403161072d640cb29/src/wren_value.h#L378-L433
 [perf]: http://munificent.github.io/wren/performance.html
 [classes]: http://munificent.github.io/wren/classes.html
+[fibers]: http://munificent.github.io/wren/fibers.html
 [embedding]: http://munificent.github.io/wren/embedding-api.html
+[try]: http://munificent.github.io/wren/getting-started.html
+[contribute]: http://munificent.github.io/wren/contributing.html