eclass-overlay: Add ml-service user and group.

Set up user and group for running the Machine Learning service in
minijail.

BUG=chromium:782499
TEST=profiles/base/accounts/display-accts.py

Change-Id: I9d0ba4a34037338bf39a7f497565312f7c1d88c2
Reviewed-on: https://chromium-review.googlesource.com/930606
Commit-Ready: Ken Turner <kennetht@chromium.org>
Tested-by: Ken Turner <kennetht@chromium.org>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
diff --git a/profiles/base/accounts/group/ml-service b/profiles/base/accounts/group/ml-service
new file mode 100644
index 0000000..e5eaf7e
--- /dev/null
+++ b/profiles/base/accounts/group/ml-service
@@ -0,0 +1,3 @@
+group:ml-service
+gid:20106
+users:chronos,ml-service
diff --git a/profiles/base/accounts/user/ml-service b/profiles/base/accounts/user/ml-service
new file mode 100644
index 0000000..d0c766c
--- /dev/null
+++ b/profiles/base/accounts/user/ml-service
@@ -0,0 +1,6 @@
+user:ml-service
+uid:20106
+gid:20106
+gecos:CrOS Machine Learning service
+home:/dev/null
+shell:/bin/false