Switch Gemfile's source to 'https://rubygems.org'

Using :rubygems is deprecated, because it defaults to HTTP. Newer 
versions of bundler refuse to run without an explicit source.
Allow setting of channel keys
Don't disable non-SSL connections when SSL is enabled
Add support for [Server] blocks in ngricd.conf
Merge branch 'set_channel_key'
Merge branch 'non_exclusive_ssl'
Merge branch 'server_blocks'