ERROR: Installation Aborted, message: Bundler could not find compatible versions for gem "stud"

[PhaedrusTheGreek]

In order to do Stud.stoppable_sleep, I have to specify stud (>= 0.0.22), which results in this when I attempt to install the plugin:

Validating logstash-input-example-0.0.1.gem
Installing logstash-input-example
Plugin version conflict, aborting
ERROR: Installation Aborted, message: Bundler could not find compatible versions for gem "stud":
  In snapshot (Gemfile.lock):
    stud (= 0.0.21)

  In Gemfile:
    stud (~> 0.0.19) java

    logstash-devutils (~> 0) java depends on
      stud (>= 0.0.20) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-output-s3 (>= 0) java depends on
      stud (~> 0.0.18) java

    logstash-output-elasticsearch_http (>= 0) java depends on
      logstash-output-elasticsearch (>= 0) java depends on
        stud (>= 0.0.17, ~> 0.0) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-output-s3 (>= 0) java depends on
      stud (~> 0.0.18) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-output-tcp (>= 0) java depends on
      stud (>= 0) java

    logstash-input-example (= 0.0.1) java depends on
      stud (>= 0.0.22) java

    stud (~> 0.0.19) java

It's probably something simple... (I hope?)