Revert "Feature: Send to multiple slack rooms at a time (#100)"
Revert "Feature: Send to multiple slack rooms at a time (#100)"

This reverts commit 7575feca8716acf52c669af7725db6054e897ed3.

Fixes #108

bioneos/redmine-slack,bioneos/redmine-slack,sciyoshi/redmine-slack,sciyoshi/redmine-slack