Add mod channel automation to tags

[benhalpern]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Description

This PR adds the functionality to map a dedicated mod channel for each tag automatically when mods are added. It also adds anyone with the mod_relations role to the channels.

After deployment
Since we already have some of these channels, we should add those channels to their appropriate tags via our console. Also add the mod relations role to relevant DEV team members.

[rhymes]

Judging from the Travis CI build output, it looks like there's something wrong in the migration (I've also noticed it didn't bump the schema version in schema.rb)

[citizen428]

Thanks for making the changes @benhalpern, LGTM! 🚀

[claassistantio]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ benhalpern
❌ Ben Halpern

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