问Weechat Ruby插件-尝试请求任何gem都会导致错误

EN

require 'mysql2'
@client = nil
def weechat_init
  Weechat.register('sql', 'Ninjex', '1.0', 'GPL3', 'Execute MySQL commands: /sql <query>', '', '')
  Weechat.hook_command('sql', 'Execute MySQL database commands', '', '', '', 'sql', '')
  return Weechat::WEECHAT_RC_OK
end

def sql(data, buffer, args)
  buffer = Weechat.current_buffer
  con_flag = '-c'
  explode = args.split(' ')
  if explode[0] == con_flag
    #Weechat.buffer_set(buffer, 'localvar_set_con', explode.drop(1).join.strip)
    con_info = explode.drop(1) # ["localhost", "username", "password", "database"]
    hostname = con_info[0]
    username = con_info[1]
    password = con_info[2]
    database = con_info[3]
    @client = Mysql2::Client.new(:host => hostname, :username => username, :password => password, :database => database)
    Weechat.print(buffer, "MySQL client created!")
  else
    row_count = 0
    Weechat.command(buffer, "Sending query: #{args}")
    sql_res = @client.query(args)
    sql_res.each(:as => :array) {|r| row_count += 1; Weechat.command(buffer, "RESULT [#{row_count.to_s}]: "+r.to_s)}
    return Weechat::WEECHAT_RC_OK
  end
end

09:27:38 =!= | ruby: error while loading file "/home/ninjex/.weechat/ruby/sql.rb"
09:27:38 =!= | ruby: error: (eval):31:in `module_eval': cannot load such file -- mysql2 (LoadError)
09:27:38 =!= | ruby: error:      from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in    `require'