Add CONTRIBUTING.md with release instructions

CONTRIBUTING.md

@@ -0,0 +1,59 @@
+# Submitting pull requests
+
+Pull requests should go via GitHub; there are some nice
+[general guidelines for contributing on GitHub](https://guides.github.com/activities/contributing-to-open-source/)
+if you haven't done it before.
+
+Unless your fix is trivial, it's a good idea to look for related
+discussions and maybe open an issue to discuss, before making a
+pull request. Discussion in advance may keep you from wasting time
+on an approach that won't work out. However, if you communicate
+better in code than in words, starting with a patch is
+fine... just be willing to revise it!
+
+Before we can accept pull requests, you will need to agree to the
+Typesafe Contributor License Agreement online, using your GitHub
+account - it takes 30 seconds.  You can do this at
+http://www.typesafe.com/contribute/cla
+
+Expect that most PRs will need revision before merge. If people
+suggest revisions, you can make them yourself or wait for a
+maintainer to do it on their own timeline. The larger the PR, the
+more revision will likely be needed.
+
+# Making a release
+
+To make a release you'll need to be a maintainer with GitHub
+permissions to push to the master and gh-pages branches, and
+Sonatype permissions to publish.
+
+Here are the steps, which should be automated but aren't (PR
+welcome!):
+
+  1. write release notes in NEWS.md following the format
+     already in there. commit.
+  2. create a signed git tag "vX.Y.Z"
+  3. start sbt; `show version` should confirm that the version was
+     taken from the tag
+  4. clean
+  5. test (double check that release works)
+  6. doc (double check that docs build, plus build docs
+     to be copied to gh-pages later)
+  7. if test or doc fails, delete the tag, fix it, start over.
+  8. publishSigned
+  9. make a separate clone of the repo in another directory and
+      check out the gh-pages branch
+  10. /bin/rm -rf latest/api on gh-pages checkout
+  11. copy config/target/api from master checkout to vX.Y.Z in
+      gh-pages so you have vX.Y.Z/index.html
+  12. copy config/target/api from master checkout into latest/
+      so you have latest/api/index.html
+  13. commit all that to gh-pages, check the diff for sanity
+      (latest/api should be mostly just changed timestamps)
+  14. push gh-pages
+  15. log into sonatype website and go through the usual hoops
+      (search for com.typesafe, verify the artifacts in it, close,
+      release)
+  16. push the "vX.Y.Z" tag
+  17. announce release, possibly wait for maven central to sync
+      first

README.md

@@ -135,6 +135,10 @@ Typesafe Contributor License Agreement online, using your GitHub
 account - it takes 30 seconds.  You can do this at
 http://www.typesafe.com/contribute/cla
 
+Please see
+[CONTRIBUTING](https://github.com/typesafehub/config/blob/master/CONTRIBUTING.md)
+for more including how to make a release.
+
 ### Build
 
 The build uses sbt and the tests are written in Scala; however,