initial working version, tested on ubuntu.
remove mongo server from requirements
Merge pull request #236 from edx/jbau-edxapp-no-install-mongoserver

remove mongo server from requirements
Handle cases where we need to refresh ruby-build due to new ruby version
Merge pull request #239 from edx/e0d/datadog

initial working version, tested on ubuntu.
Merge pull request #237 from edx/jbau/ruby/always-update-ruby-build

Handle cases where we need to refresh ruby-build due to new ruby version
sandbox-ora: Allow to configure the user used by ORA
sandbox-ora: Add xqueue/ORA to sandbox & switch to `virtualenv` role
sandbox-ora: Add SERVICE_VARIANT to xqueue to customize filenames

To be used in conjonction with
https://github.com/antoviaque/xqueue/commit/303601ea9ffcbd30f6bb3e2b9a42d6f85fbcf6b3

This is necessary to be able to get several services using the
`/opt/wwc/env.json` & `/opt/wwc/auth.json` files. The configuration
files would get overwitten when this is used by several different
services cohabiting on a single instance
sandbox-ora: Fixes `NaN` in config when nb of cores is incorrectly detected
sandbox-ora: Add missing '/' in configuration of open ended interface
sandbox-ora: Switch to HTTP for contacting Xqueue to match LMS defaults
sandbox-ora: Allow to configure Rabbitmq binding IP & use localhost for sandbox
sandbox-ora: Create edx user expected by xqueue in rabbitmq
sandbox-ora: Parametrize the variables used for ORA's virtualenv
sandbox-ora: Create dedicated user & virtualenv for xqueue

Since xqueue has its own set of dependencies, using a dedicated
virtualenv allows to avoid potential dependencies conflicts when
several services are installed on the same instance.
sandbox-ora: Add SERVICE_VARIANT to ORA to customize filenames

This is necessary to be able to get several services using the
`/opt/wwc/env.json` & `/opt/wwc/auth.json` files. The configuration
files would get overwitten when this is used by several different
services cohabiting on a single instance