diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b0600b194ac2a8edd0e77f6e8c0c60114c93a5d0..ef61d07ab26b88a292afd6bc0fe53c492cacf8ef 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,7 +2,7 @@ image: docker:19.03.12
 
 variables:
   DOCKER_TLS_CERTDIR: "/certs"
-  IMAGE_VER: 4.2.1-passenger-12
+  IMAGE_VER: 4.2.1-passenger-13
 
 services:
   - docker:19.03.12-dind
diff --git a/.gitmodules b/.gitmodules
index dba48f3e0b3e6cd43dc43dbe682b84c4429cdabf..45084dcd385151c49f303dede00f66fa597bcdda 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -19,3 +19,6 @@
 [submodule "plugins/redmine_work_time"]
 	path = plugins/redmine_work_time
 	url = https://github.com/tkusukawa/redmine_work_time.git
+[submodule "plugins/sparkline"]
+	path = plugins/sparkline
+	url = https://gitlab.pirati.cz/sperling/redmine-sparkline-plugin.git
diff --git a/plugins/sparkline b/plugins/sparkline
new file mode 160000
index 0000000000000000000000000000000000000000..53970b5d80d0787f8830667fbdfeab8709dfcae8
--- /dev/null
+++ b/plugins/sparkline
@@ -0,0 +1 @@
+Subproject commit 53970b5d80d0787f8830667fbdfeab8709dfcae8