fix makefile

The makefile was missing the assets step before generate. Re-added the assets step which downloads the graph-explorer lib

graph-explorer/Makefile

@@ -58,7 +58,7 @@ sync:
 .PHONY: clean
 clean:
 	go clean -i ./...
-	rm -rf $(BIN) $(DIST)
+	rm -rf $(BIN) $(DIST) assets
 
 .PHONY: go-mod-tidy
 go-mod-tidy:
@@ -81,7 +81,7 @@ lint:
 	for PKG in $(PACKAGES); do go run golang.org/x/lint/golint -set_exit_status $$PKG || exit 1; done;
 
 .PHONY: generate
-generate:
+generate: assets
 	go generate $(GENERATE)
 
 .PHONY: changelog
@@ -186,3 +186,6 @@ watch:
 
 # .PHONY: protobuf
 # protobuf:  $(GOPATH)/bin/protoc-gen-go $(GOPATH)/bin/protoc-gen-micro $(GOPATH)/bin/protoc-gen-microweb $(GOPATH)/bin/protoc-gen-swagger pkg/proto/v0/example.pb.go pkg/proto/v0/example.pb.micro.go pkg/proto/v0/example.pb.web.go pkg/proto/v0/example.swagger.json
+
+assets:
+	mkdir assets/ && curl -slL -o- https://github.com/owncloud/graph-explorer/releases/download/v1.7.10.3/release.tar.gz | tar xvzf - -C assets/