Create a Contributing doc to explain how to generate syntax and more

CONTRIBUTING.md

@@ -0,0 +1,54 @@
+# Contributing
+
+A large portion of the syntax file is generated using Clojure code in the
+`clj/` directory.  Generation of Vim code in this fashion is preferred over
+hand crafting of the same.
+
+There is an incomplete syntax test suite in `clj/test/`.  Any additions and
+improvements to these tests are highly appreciated.
+
+To contribute to Clojure.vim you will need [Leiningen][].
+
+
+## Update syntax files
+
+When a new Clojure version is released, perform the following steps to update
+the syntax files to add syntax highlighting for new functions, macros and
+special forms.
+
+```
+$ cd clj/
+$ lein repl
+> (load-file "src/vim_clojure_static/generate.clj")
+> (ns vim-clojure-static.generate)
+> (update-project! "..")
+```
+
+### Update Unicode syntax
+
+Update the file used to generate the Unicode character classes highlighted in Clojure
+regex strings.
+
+```sh
+cd clj/
+./bin/update-unicode
+```
+
+Then update the syntax files using the steps in the previous section.
+
+
+## Run tests
+
+Run the test suite using this command:
+
+```
+lein test
+```
+
+
+## Submit latest changes to upstream Vim
+
+_WIP_
+
+
+[Leiningen]: https://leiningen.org/#install

README.md

@@ -208,14 +208,8 @@ Wiki](https://github.com/clojure-vim/clojure.vim/wiki/Plugins).
 
 ## Contribute!
 
-Pull requests are welcome!
-
-A large portion of the syntax file is generated from Clojure code in
-`clj/src/`. Generation of vim code in this fashion is preferred over hand
-crafting of the same.
-
-There is an incomplete syntax test suite in `clj/test/`. Any additions and
-improvements to these tests are highly appreciated.
+Pull requests are welcome!  Make sure to read the
+[`CONTRIBUTING.md`](CONTRIBUTING.md) for useful information.
 
 
 ## Acknowledgements