Add support for specifying the UID and GID values

container/run-as-user

@@ -1,19 +1,37 @@
 #!/bin/sh
 
 ##############################################################################
-# By default, change the dev user's uid and gid to match the user that owns
-# the project directory and run a command as that user. If a ~/.ssh directory
-# exists and it's not owned by root then switch and run as that user instead
-# to use public key authentication.
+# If a PUID/PGID enviroment variable exists, use those values for the `uid`
+# and `gid` when executing scripts, otherwise change the dev user's uid and
+# gid to match the user that owns the project directory and run a command as
+# that user. If a ~/.ssh directory exists and it's not owned by root then
+# switch and run as that user instead in order to take advantage of public key
+# authentication.
 ##############################################################################
 
 stat_dir="/src"
 if [ -d "/home/dev/.ssh" ] && [ "0" != "$(stat -c '%g' /home/dev/.ssh)" ] && [ "0" != "$(stat -c '%u' /home/dev/.ssh)" ]; then
     stat_dir="/home/dev/.ssh"
 fi
 
-groupmod -g $(stat -c '%g' $stat_dir) -o dev > /dev/null 2>&1
-usermod -u $(stat -c '%u' $stat_dir) -o dev > /dev/null 2>&1
+# if the PUID environment variable exists, assume that is the preferred user id,
+# otherwise use the $stat_dir
+if [ "" != "$PUID" ]; then
+    uid=$PUID
+else
+    uid=$(stat -c '%u' $stat_dir)
+fi
+
+# if the PGID environment variable exists, assume that is the preferred group id,
+# otherwise use the $stat_dir
+if [ "" != "$PGID" ]; then
+    gid=$PGID
+else
+    gid=$(stat -c '%g' $stat_dir)
+fi
+
+groupmod -g $gid -o dev > /dev/null 2>&1
+usermod -u $uid -o dev > /dev/null 2>&1
 chown -R dev:dev ~dev/ > /dev/null 2>&1
 
 sudo -u dev $@