Pin disclaimer to message in each bridged channel

[patcon]

Related: https://github.com/edgi-govdata-archiving/overview/issues/154

Slack context: https://edgi.slack.com/archives/C4H23J40J/p1502400481729122?thread_ts=1502381075.026913&cid=C4H23J40J

For ease of updating, I have to text in one place in a hackmd notepad: https://hackmd.io/s/BJWOLQBrZ

To Do

• [x] Add disclaimer link in pinned post to all channels
• [x] Create ticket upstream to track this new deficiency of bridge (shared posts not going through)

[dcwalk]

In addition to Pinning @patcon, can we edit the purpose & topic? I find that I almost never see the Pinned messages until much later when joining a channel, some prompt in the description would help

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in seven days if no further activity occurs. If it should not be closed, please comment! Thank you for your contributions.

[dcwalk]

I think this might be a good thing to verify at least on the EDGI end, also quick. Thoughts @lightandluck?

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in seven days if no further activity occurs. If it should not be closed, please comment! Thank you for your contributions.

[lightandluck]

I've added new pinned messages to each bridged channel and edited the topics of the channels with more information on bridging: https://hackmd.io/3fZbzWBfRZGpbpD_V-1GhQ?view

Also opened a related issue: #234