How to add dependency for existing gems

Hi All,

I am new to jruby

I want to add gssapi support for logstash-output-elasticsearch

so I modify some code on elasticsearch-transport gem

export GEM_HOME=$LOGSTASH_HOME/vendor/bundle/jruby/1.9
export GEM_PATH=""

vendor/jruby/bin/jruby vendor/jruby/bin/gem install gssapi

after I start the logstash instance, I got no such file to load -- gssapi error

Since I already install gssapi, why I get such error? How can I solve this error?

one solution, after install new gem, add the gem in the logstash gem file, run logstash once to update the lock file