[CI] Install docker explicitly before trying to use it

.circleci/config.yml

@@ -35,7 +35,28 @@ jobs:
       - setup_remote_docker
 
       - run:
-          name: build docker image
+          #FIXME: Bake this into the base image
+          name: install docker
+          command: |
+            apt-get update
+
+            apt-get install --yes \
+                 apt-transport-https \
+                 ca-certificates \
+                 curl \
+                 gnupg2 \
+                 software-properties-common
+
+            curl -fsSL https://download.docker.com/linux/debian/gpg | sudo apt-key add -
+            add-apt-repository \
+                "deb [arch=amd64] https://download.docker.com/linux/debian \
+                $(lsb_release -cs) \
+                stable"
+
+            apt-get update
+            apt-get install docker-ce
+        - run:
+            name: build CI image
             command: |
                docker build -t tljh-systemd .