Gotcha, yeah seemed to be the same error as I reported yesterday (from upgrading a different forum) so figured it was the same thing here, but maybe there are a couple different errors.
Here's my output from running 'docker images' just now (after rebuild)
REPOSITORY TAG IMAGE ID CREATED SIZE
local_discourse/app latest 5e19cae035fb 2 hours ago 2.79GB
discourse/base 2.0.20191013-2320 09725007dc9e 7 weeks ago 2.3GB
<none> <none> a2d7facd2177 3 months ago 2.62GB
discourse/base 2.0.20190901-2315 10f636afbeaf 3 months ago 2.29GB
<none> <none> 0f97a7329641 6 months ago 2.3GB
discourse/base 2.0.20190505-2322 ed87227f60d2 7 months ago 1.91GB
<none> <none> fbd01a7c0342 9 months ago 2.27GB
discourse/base 2.0.20190217 9c24db193c37 9 months ago 1.92GB