Updating GitLab Mattermost to v1.2 fo GitLab 8.2 release

Opening a ticket for the update of GitLab Mattermost to v1.2 in GitLab omnibus

• Final Mattermost v1.2 release will be Nov 16 from http://www.mattermost.org/download/

• Mattermost v1.2-RC1 is available now for download and testing at https://gitlab.mattermost.com/community

Key updates for GitLab Mattermost v1.2

• Hubot, IRC, RSS and other [community-created GitLab Mattermost applications] (www.mattermost.org/community-applications/) can now connect to Mattermost over incoming and outgoing webhooks
• Syntax highlighting now available by adding name of language to first line of code block, e.g. ```python
• New GitLab Mattermost Administrator's Guide consolidates post-install guidance on support resources, configuration, upgrade, and trouble-shooting

Full release notes can be found here

Proposed changes to GitLab omnibus 8.2

1. There are three additional settings added to config.json Mattermost in v1.2, which we propose are added to omnibus using the default settings listed below:

   • Under TeamSettings in config.json:
     • Added: "RestrictTeamNames": true to control whether team names can contain reserved words like www, admin, support, test, etc.
     • Added: "EnableTeamListing": false to control whether teams can be listed on the root page of the site
   • Under ServiceSettings in config.json
     • Added: EnableOutgoingWebhooks": true to turn on outgoing webhooks

2. Propose setting mattermost['email_enable_sign_up_with_email'] = false as users are confused with having both GitLab SSO and email options available.

3. Per #941 (closed) propose enabling error-level logging to help users troubleshoot installs:

mattermost['log_enable_file'] = true
mattermost['log_file_level'] = 'ERROR'
mattermost['log_file_directory'] = '/var/log/gitlab/mattermost/mattermost.log'

Logging settings are documented here as FYI.

PS: We're continuing to work on usability and documentation improvements for GitLab Mattermost users