project: try alexellis/derek bot to manage PRs and issues

Signed-off-by: Tibor Vass <tibor@docker.com>

.DEREK.yml

@@ -0,0 +1,17 @@
+curators:
+  - aboch
+  - alexellis
+  - andrewhsu
+  - anonymuse
+  - chanwit
+  - ehazlett
+  - fntlnz
+  - gianarb
+  - mgoelzer
+  - programmerq
+  - rheinwein
+  - ripcurld0
+  - thajeztah
+
+features:
+  - comments

CONTRIBUTING.md

@@ -311,6 +311,36 @@ Don't forget: being a maintainer is a time investment. Make sure you
 will have time to make yourself available. You don't have to be a
 maintainer to make a difference on the project!
 
+### Manage issues and pull requests using the Derek bot
+
+If you want to help label, assign, close or reopen issues or pull requests
+without commit rights, ask a maintainer to add your Github handle to the 
+`.DEREK.yml` file. [Derek](https://github.com/alexellis/derek) is a bot that extends
+Github's user permissions to help non-committers to manage issues and pull requests simply by commenting.
+
+For example:
+
+* Labels
+
+```
+Derek add label: kind/question
+Derek remove label: status/claimed
+```
+
+* Assign work
+
+```
+Derek assign: username
+Derek unassign: me
+```
+
+* Manage issues and PRs
+
+```
+Derek close
+Derek reopen
+```
+
 ## Moby community guidelines
 
 We want to keep the Moby community awesome, growing and collaborative. We need