diff --git a/.circleci/config.yml b/.circleci/config.yml
index ea8a53719..b102175b7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -75,9 +75,9 @@ jobs:
       - checkout
       - setup_remote_docker:
           version: 17.10.0-ce
-      - run: docker build --build-arg git_tag=$(git describe --tags) --build-arg git_commit=$(git rev-parse HEAD) -f Dockerfile -t oryd/keto:$CIRCLE_TAG .
+      - run: docker build --build-arg git_tag=$(git describe --tags) --build-arg git_commit=$(git rev-parse HEAD) -f Dockerfile -t oryd/keto:$(echo $CIRCLE_TAG | tr '+' '_') .
       - run: docker login --username "$DOCKER_USERNAME" --password "$DOCKER_PASSWORD"
-      - run: docker push oryd/keto:$CIRCLE_TAG
+      - run: docker push oryd/keto:$(echo $CIRCLE_TAG | tr '+' '_')
 
   publish-docs:
     docker:
diff --git a/Gopkg.lock b/Gopkg.lock
index dd4b9fc83..53a25e762 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -313,7 +313,6 @@
   version = "v0.8.9"
 
 [[projects]]
-  branch = "master"
   name = "github.com/ory/metrics-middleware"
   packages = ["."]
   revision = "74602156c5c0b9617e12e4663a366516fec6cab4"
@@ -552,6 +551,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "994b70f0ae1554b715f5f4edc95ff57b4fc1ce7f82cea19b0b82e0984096b057"
+  inputs-digest = "c352603ce731f525f48699b47bface334dca3ab3450db84010a30ce30198fa33"
   solver-name = "gps-cdcl"
   solver-version = 1
diff --git a/Gopkg.toml b/Gopkg.toml
index 9c43c6249..bc42af346 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -25,6 +25,10 @@
 #   unused-packages = true
 
 
+[[constraint]]
+  name = "github.com/ory/metrics-middleware"
+  revision = "74602156c5c0b9617e12e4663a366516fec6cab4"
+
 [[constraint]]
   name = "github.com/akutz/gotil"
   version = "0.1.0"
diff --git a/cmd/server/serve.go b/cmd/server/serve.go
index e6876b6bb..cd932e0dc 100644
--- a/cmd/server/serve.go
+++ b/cmd/server/serve.go
@@ -38,7 +38,7 @@ import (
 	"github.com/ory/keto/role"
 	"github.com/ory/keto/warden"
 	"github.com/ory/ladon"
-	"github.com/ory/metrics-middleware"
+	metrics "github.com/ory/metrics-middleware"
 	"github.com/rs/cors"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
diff --git a/warden/sdk_test.go b/warden/sdk_test.go
index cc013bbea..32e53067c 100644
--- a/warden/sdk_test.go
+++ b/warden/sdk_test.go
@@ -32,6 +32,7 @@ import (
 	"github.com/ory/keto/authentication"
 	keto "github.com/ory/keto/sdk/go/keto/swagger"
 	"github.com/ory/keto/warden"
+
 	//"github.com/ory/ladon"
 	"github.com/pkg/errors"
 	//"github.com/stretchr/testify/assert"