[etherpad-web/oscp-backend] Clone the theme branch to skins directory

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit fe4be6df341929e7a9e576c7d86f49d298a03fa8
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Wed May 20 11:44:15 2020 +0200

    Clone the theme branch to skins directory

 Dockerfile | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/Dockerfile b/Dockerfile
index 98710bd..26d3fe5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,6 +16,7 @@ RUN cd /opt && curl -SL \
 
 RUN groupadd etherpad -g 1000180000  && \
     useradd etherpad -g 1000180000 -u 1000180000 -G etherpad -r -l -M -d /opt/etherpad && \
+    git clone --single-branch --branch theme --depth 1 https://gitlab.gnome.org/Infrastructure/etherpad-web 
/opt/etherpad/src/static/skins/gnome && \
     chown -R etherpad:etherpad /opt/etherpad
 
 ADD entrypoint.sh /entrypoint.sh