feat(docker): allow user-customizable ssh host keys

There is a new ./data bind mount used here. If ssh_host_* keys are
in ./data when the git service starts, they'll override the
container-generated host keys.

Signed-off-by: Kevin Morris <kevr@0cost.org>

docker-compose.aur-dev.yml

@@ -18,6 +18,7 @@ services:
     restart: always
     volumes:
       - ${GIT_DATA_DIR}:/aurweb/aur.git
+      - ./data:/aurweb/data
       - cache:/cache
 
   smartgit:

docker/git-entrypoint.sh

@@ -60,6 +60,13 @@ sed -ri "s|^(ssh-cmdline) = .+|\1 = $ssh_cmdline|" $AUR_CONFIG_DEFAULTS
 # Setup SSH Keys.
 ssh-keygen -A
 
+# In docker-compose.aur-dev.yml, we bind ./data to /aurweb/data.
+# Production users wishing to include their own SSH keys should
+# supply them in ./data.
+if [ -d /aurweb/data ]; then
+    find /aurweb/data -type f -name 'ssh_host_*' -exec cp -vf "{}" /etc/ssh/ \;
+fi
+
 # Taken from INSTALL.
 mkdir -pv $GIT_REPO