diff --git a/config-joey.hs b/config-joey.hs
index dec2701..f791ed3 100644
--- a/config-joey.hs
+++ b/config-joey.hs
@@ -133,10 +133,10 @@ orca = standardSystem "orca.kitenet.net" Unstable "amd64"
 
 	& Systemd.nspawned (GitAnnexBuilder.autoBuilderContainer
 		GitAnnexBuilder.standardAutoBuilder
-		(System (Debian Testing) "amd64") fifteenpast "2h")
+		(System (Debian Unstable) "amd64") fifteenpast "2h")
 	& Systemd.nspawned (GitAnnexBuilder.autoBuilderContainer
 		GitAnnexBuilder.standardAutoBuilder
-		(System (Debian Testing) "i386") fifteenpast "2h")
+		(System (Debian Unstable) "i386") fifteenpast "2h")
 	& Systemd.nspawned (GitAnnexBuilder.androidAutoBuilderContainer
 		(Cron.Times "1 1 * * *") "3h")
   where
diff --git a/debian/changelog b/debian/changelog
index f4459a2..2441f4a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,4 +1,4 @@
-propellor (2.5.0) UNRELEASED; urgency=medium
+propellor (2.5.0) unstable; urgency=medium
 
   * cmdProperty' renamed to cmdPropertyEnv to make way for a new,
     more generic cmdProperty' (API change)
@@ -24,8 +24,10 @@ propellor (2.5.0) UNRELEASED; urgency=medium
   * Docker: volume and publish accept Bound FilePath and Bound Port,
     respectively. They also continue to accept Strings, for backwards
     compatability.
+  * Docker: Added environment property.
+    Thanks Antoine Eiche.
 
- -- Joey Hess <id@joeyh.name>  Thu, 07 May 2015 12:08:34 -0400
+ -- Joey Hess <id@joeyh.name>  Tue, 09 Jun 2015 17:08:43 -0400
 
 propellor (2.4.0) unstable; urgency=medium
 
diff --git a/propellor.cabal b/propellor.cabal
index 9edc143..d09e759 100644
--- a/propellor.cabal
+++ b/propellor.cabal
@@ -1,5 +1,5 @@
 Name: propellor
-Version: 2.4.0
+Version: 2.5.0
 Cabal-Version: >= 1.6
 License: BSD3
 Maintainer: Joey Hess <id@joeyh.name>
diff --git a/src/Propellor/Property/Docker.hs b/src/Propellor/Property/Docker.hs
index 1dcc352..d3e60fc 100644
--- a/src/Propellor/Property/Docker.hs
+++ b/src/Propellor/Property/Docker.hs
@@ -34,6 +34,7 @@ module Propellor.Property.Docker (
 	memory,
 	cpuShares,
 	link,
+	environment,
 	ContainerAlias,
 	restartAlways,
 	restartOnFailure,
@@ -348,6 +349,11 @@ restartOnFailure (Just n) = runProp "restart" ("on-failure:" ++ show n)
 restartNever :: Property HasInfo
 restartNever = runProp "restart" "no"
 
+-- | Set environment variable with a tuple composed by the environment
+-- variable name and its value.
+environment :: (String, String) -> Property HasInfo
+environment (k, v) = runProp "env" $ k ++ "=" ++ v
+
 -- | A container is identified by its name, and the host
 -- on which it's deployed.
 data ContainerId = ContainerId