Lock RubyDNS to 0.8.x versions

[swrobel]

Invoker currently does not start on a new install because it will use RubyDNS 0.9.0 which was released on 10/23/14. This took an exceptionally long time to troubleshoot because of celluloid, but I finally tracked it down! Invoker's gemspec locks RubyDNS to ~> 0.7, however the author states that 0.x releases are incompatible, but minor versions should be compatible. Here is the offending change in 0.9.0.
For the time being you can add the following to your own Gemfile:

gem 'rubydns', '~> 0.8.5'

Here is a trace of what happens when you run with RubyDNS 0.9.0:

→ invoker start Procfile 
D, [2014-10-26T09:45:30.515304 #59891] DEBUG -- : Terminating 1 actor...
vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/calls.rb:39:in `check': wrong number of arguments (1 for 0) (ArgumentError)
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/calls.rb:24:in `dispatch'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/calls.rb:63:in `dispatch'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/cell.rb:60:in `block in invoke'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/cell.rb:71:in `block in task'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/actor.rb:357:in `block in task'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/tasks.rb:57:in `block in initialize'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/tasks/task_fiber.rb:15:in `block in create'
    from (celluloid):0:in `remote procedure call'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/calls.rb:92:in `value'
    from vendor/bundle/gems/celluloid-0.16.0/lib/celluloid/proxies/sync_proxy.rb:33:in `method_missing'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/power/powerup.rb:17:in `block in run'
    from vendor/bundle/bundler/gems/eventmachine-4d53154a9ea4/lib/eventmachine.rb:187:in `call'
    from vendor/bundle/bundler/gems/eventmachine-4d53154a9ea4/lib/eventmachine.rb:187:in `run_machine'
    from vendor/bundle/bundler/gems/eventmachine-4d53154a9ea4/lib/eventmachine.rb:187:in `run'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/power/powerup.rb:13:in `run'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/power/powerup.rb:7:in `block in fork_and_start'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/power/powerup.rb:7:in `fork'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/power/powerup.rb:7:in `fork_and_start'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/process_manager.rb:72:in `run_power_server'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/commander.rb:39:in `start_manager'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/cli.rb:46:in `start'
    from vendor/bundle/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
    from vendor/bundle/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
    from vendor/bundle/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'
    from vendor/bundle/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
    from vendor/bundle/gems/invoker-1.3.0/lib/invoker/cli.rb:12:in `start'
    from vendor/bundle/gems/invoker-1.3.0/bin/invoker:7:in `<top (required)>'
    from ./bin/invoker:16:in `load'
    from ./bin/invoker:16:in `<main>'

[gnufied]

@swrobel thank your tracking this down!

@ioquatix Invoker has some bits that depends on Eventmachine outside the scope of RubyDNS. we will migrate to 0.9.0 of RubyDNS soon, but in the process - I would like to completely remove dependency on Eventmachine, so it may take a bit of time.

[ioquatix]

@gnufied Awesome. Just so you know, I'm not advocating you move away from EventMachine, just that for RubyDNS it was a dead end, IMHO.

[swrobel]

@gnufied can you roll a new gem version?

[ami7ava]

Done.