Add some contributor docs

README.md

@@ -321,3 +321,12 @@ installation.
 
 [2]: http://localhost:6060/pkg/github.com/spf13/pflag
 [3]: http://godoc.org/github.com/spf13/pflag
+
+## Contributing
+
+Is `pflag` not doing all you think it should? Or did you find a bug just now? We welcome contributions of all kinds - a well-written issue is just as
+valuable as a pull request! If you're uncertain whether a feature addition would be accepted, you can always file an issue to discuss it, before you
+start working on the implementation.
+
+Reviewing, merging and releasing new versions is done by a group of co-maintainers in our spare time, so response times might be erratic. Long response
+times do *not* signal that we do not value your contribution.

RELEASING.md

@@ -0,0 +1,20 @@
+# Releasing a new version
+
+Releasing a new version is very simple, but documented here to enable any maintainer with enough access to help out.
+We release new versions whenever there are changes that seem valuable to make available for consumption.
+
+To create a new relase:
+
+1. Go to the [releases page](https://github.com/spf13/pflag/releases) on Github, and select
+[Draft a new release](https://github.com/spf13/pflag/releases/new).
+
+2. Click the tag selector, and create a new tag named `vX.Y.Z`, where `X.Y.Z` is the semantic version number
+   of the new version. (Use your judgement when deciding whether to increment patch or minor version; increment
+   major version if there are deliberate breaking changes to exported APIs or documented behaviors).
+
+3. Click `Generate release notes` to generate a writeup that includes all merged changes since the last release,
+   and all first-time contributors. Add a section at the top with some info about the relase if there is any
+   relevant info to share.
+
+4. Either save your release as a draft (remember to re-generate release notes when you come back to publish it!)
+   or publish it directly. Github will automatically create the appropriate git tag when the relase is published.