Add infrastructure for an server extras image

This is based on the standalone image from https://github.com/ome/omero-web-docker/tree/5.6.0-m4
This just provides the infrastructure for building the extras image, it doesn't install or change anything (see ome#21 instead)

Makefile

@@ -65,13 +65,20 @@ endif
 ifndef BUILD
 	$(eval BUILD=0)
 endif
-	docker build -t $(REPO)/omero-server:$(VERSION)-$(BUILD) .
+	docker build $(BUILDARGS) -t $(REPO)/omero-server:$(VERSION)-$(BUILD) .
 	docker tag $(REPO)/omero-server:$(VERSION)-$(BUILD) $(REPO)/omero-server:$(VERSION)
 	@MAJOR_MINOR=$(shell echo $(VERSION) | cut -f1-2 -d. );\
 	docker tag $(REPO)/omero-server:$(VERSION)-$(BUILD) $(REPO)/omero-server:$$MAJOR_MINOR
 
+	docker build --build-arg=PARENT_IMAGE=$(REPO)/omero-server:$(VERSION) -t $(REPO)/omero-server-extras:$(VERSION)-$(BUILD) extras
+	docker tag $(REPO)/omero-server-extras:$(VERSION)-$(BUILD) $(REPO)/omero-server-extras:$(VERSION)
+	@MAJOR_MINOR=$(shell echo $(VERSION) | cut -f1-2 -d. );\
+	docker tag $(REPO)/omero-server-extras:$(VERSION)-$(BUILD) $(REPO)/omero-server-extras:$$MAJOR_MINOR
+
+
 docker-build: docker-build-versions
 	docker tag $(REPO)/omero-server:$(VERSION)-$(BUILD) $(REPO)/omero-server:latest
+	docker tag $(REPO)/omero-server-standalone:$(VERSION)-$(BUILD) $(REPO)/omero-server-extras:latest
 
 
 docker-push-versions:
@@ -86,5 +93,11 @@ endif
 	@MAJOR_MINOR=$(shell echo $(VERSION) | cut -f1-2 -d. );\
 	docker push $(REPO)/omero-server:$$MAJOR_MINOR
 
+	docker push $(REPO)/omero-server-extras:$(VERSION)-$(BUILD)
+	docker push $(REPO)/omero-server-extras:$(VERSION)
+	@MAJOR_MINOR=$(shell echo $(VERSION) | cut -f1-2 -d. );\
+	docker push $(REPO)/omero-server-extras:$$MAJOR_MINOR
+
 docker-push: docker-push-versions
 	docker push $(REPO)/omero-server:latest
+	docker push $(REPO)/omero-server-extras:latest

extras/01-default-extras.omero

@@ -0,0 +1 @@
+# OMERO.server extras

extras/Dockerfile

@@ -0,0 +1,9 @@
+ARG PARENT_IMAGE=openmicroscopy/omero-server:latest
+FROM ${PARENT_IMAGE}
+MAINTAINER [email protected]
+
+USER root
+
+ADD 01-default-extras.omero /opt/omero/server/config/
+
+USER omero-server