起きたエラー
Production(本番)環境
NameError (uninitialized constant Net::HTTP):
原因と解決
# ↓の行を追記
require 'net/http'
http = Net::HTTP.new(uri.host, uri.port)
Development(開発)環境だと必要ないみたい
参考
https://github.com/AzureAD/omniauth-azure-activedirectory/issues/33
https://teratail.com/questions/112198