Add a Community page

Closes #257.

doc/site/community.markdown

@@ -0,0 +1,34 @@
+^title Community
+^category reference
+
+Like the [wren bird](https://en.wikipedia.org/wiki/Wren), Wren's community is
+small. But it exists!
+
+## User groups
+
+There's only one Wren user group, and it's the [official Wren mailing
+list](https://groups.google.com/forum/#!forum/wren-lang). Please join it and
+say hello! There are no strangers to Wren, just friends we haven't met yet.
+
+## Third-party libraries
+
+There are some third-party libraries that are written in Wren. Here's the list:
+
+- [wren-test](https://github.com/gsmaverick/wren-test), a testing framework
+- [Please](https://github.com/EvanHahn/wren-please), an assertion library
+- [wren-colors](https://github.com/gsmaverick/wren-colors) for printing colored
+  messages to the terminal
+- [3D vectors for Wren](https://github.com/EvanHahn/wren-vector3d)
+
+A few people have also added embedding APIs for Wren:
+
+- [Rust: tilpner/wren-sys](https://github.com/tilpner/wren-sys)
+- [Rust: pwoolcoc/wren-sys](https://github.com/pwoolcoc/wren-sys)
+- [Rust: pwoolcoc/wren-rs](https://github.com/pwoolcoc/wren-rs)
+
+## Editor integrations
+
+If you want Wren syntax highlighting in your editor, look no further:
+
+- [Vim](https://github.com/lluchs/vim-wren)
+- [Emacs](https://github.com/v2e4lisp/wren-mode.el)