记录下遇到的问题：

提示ruby错误

$gem install gollum

ERROR:  Could not find a valid gem ‘gollum‘ (>= 0), here is why:

          Unable to download data from https://rubygems.org/ - SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://api.rubygems.org/specs.4.8.gz)

$ ruby --version

ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin14]

执行gem update

$ gem update

Updating installed gems

ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)

    SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://api.rubygems.org/specs.4.8.gz)

查询各种资料

rvm reinstall 2.2.0 --disable-binary

安装成功后还是不行

$ gem update

Updating installed gems

ERROR:  SSL verification error at depth 2: certificate has expired (10)

ERROR:  Certificate /C=BE/O=GlobalSign nv-sa/OU=Root CA/CN=GlobalSign Root CA expired at 2014-01-28T12:00:00Z

ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)

    SSL_connect returned=1 errno=0 state=error: certificate verify failed (https://api.rubygems.org/specs.4.8.gz)

按照提示升级到 ruby 2.4.0

$ rvm reinstall 2.4.0 --disable-binary

$ ruby -v

ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-darwin14]

继续尝试命令 下载。。。安装 擦还是不行

$ gem install gollum

Fetching: charlock_holmes-0.7.3.gem (100%)

Building native extensions.  This could take a while...

ERROR:  Error installing gollum:

ERROR: Failed to build gem native extension.

    current directory: /Users/xxx/.rvm/gems/ruby-2.4.0/gems/charlock_holmes-0.7.3/ext/charlock_holmes

/Users/xxxg/.rvm/rubies/ruby-2.4.0/bin/ruby -r ./siteconf20170519-13239-1e10mne.rb extconf.rb

checking for -licui18n... no

checking for -licui18n... no

***************************************************************************************

*********** icu required (brew install icu4c or apt-get install libicu-dev) ***********

***************************************************************************************

*** extconf.rb failed ***

Could not create Makefile due to some reason, probably lack of necessary

libraries and/or headers.  Check the mkmf.log file for more details.  You may

need configuration options.

Provided configuration options:

--with-opt-dir

--with-opt-include

--without-opt-include=${opt-dir}/include

--with-opt-lib

--without-opt-lib=${opt-dir}/lib

--with-make-prog

--without-make-prog

--srcdir=.

--curdir

--ruby=/Users/xxx/.rvm/rubies/ruby-2.4.0/bin/$(RUBY_BASE_NAME)

--with-icu-dir

--without-icu-dir

--with-icu-include

--without-icu-include=${icu-dir}/include

--with-icu-lib

--without-icu-lib=${icu-dir}/lib

--with-icui18nlib

--without-icui18nlib

--with-icui18nlib

--without-icui18nlib

To see why this extension failed to compile, please check the mkmf.log which can be found here:

按照提示继续安装 brew install icu4c

安装成功后

 gem install gollum

ERROR:  While executing gem ... (Errno::ENOENT)

    No such file or directory - getcwd

执行 

gem update

成功后：执行 

gem install gollum

等待安装。

gem install gollum