報錯：YAML safe loading is not available. Please upgrade psych to a version that supports safe loading (>= 2.0).
ERROR:? SSL verification error at depth 1: unable to get local issuer certificate (20)
ERROR:? You must add /O=Digital Signature Trust Co./CN=DST Root CA X3 to your local trusted store
ERROR:? SSL verification error at depth 2: self signed certificate in certificate chain (19)
ERROR:? Root certificate is not trusted (/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA)
ERROR:? SSL verification error at depth 2: self signed certificate in certificate chain (19)
ERROR:? Root certificate is not trusted (/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA)
查看版本：rvm -v
查詢結(jié)果：rvm 1.29.3 (latest) by Michal Papis, Piotr Kuczynski, Wayne E. Seguin [https://rvm.io]
獲取版本：rvm list known
升級ruby版本：rvm install 2.3.0
錯誤結(jié)果：Error running '__rvm_make -j 1',
please read /Users/jiaweibo/.rvm/log/1510919754_ruby-2.3.0/make.log
There has been an error while running make. Halting the inst
錯誤結(jié)果：fatal: unable to access 'https://github.com/Homebrew/homebrew/': SSLRead() return error -9806 (這個原因是被墻了.)
我的解決辦法是弄個代理,重新安裝一遍,就OK了
可能是問題所在，其原因在于沒有安裝Xcode的CommandLineTools工具
執(zhí)行下面的代碼：xcode-select --install
會彈出安裝框，一路next，完畢后就可以安裝Ruby了
rvm install 2.3.0
最后安裝或者升級cocoapods：sudo gem update/install cocoapods
