[SAC] Slack and OSGeo

[Jeff McKenna]

There is now actually an OSGeo "team" on Slack 
(https://osgeo.slack.com/signup), which is great, but we need to figure 
out a way to allow anyone to register.  (and there is also a #MapServer 
channel)

Credit to Stephan Meissl for setting this up during the code sprint at 
FOSS4G-Como.

I am a team "Owner" so I can help configure.

Does anyone have an idea for how to allow people to join with their own 
e-mail addresses, so we can share this?

-jeff