这个装cocoapods 遇到了好多问题，折腾了几天总算装好了，下面说下步骤，省的其他小伙伴踩坑。
1.首先设置ruby源
gem sources -l #查看当前ruby源
gem sources --remove https://rubygems.org/ #移除当前ruby源
gem sources -a https://gems.ruby-china.org/ #设置当前ruby源
2.更新gem
sudo gem update --system
3.安装cocoapods
sudo gem install -n /usr/local/bin cocoapods
下一步执行 pod setup，然后坑就来了，试了好多次都失败
报错如下：
[!] /usr/bin/git clonehttps://github.com/CocoaPods/Specs.git master
Cloning into 'master'...
error: RPC failed; curl 56 SSLRead() return error -36
fatal: The remote end hung up unexpectedly
fatal: early EOF
fatal: index-pack failed
试了各种方式也解决不了，包括直接下载Cocoapods包放到～／.cocoapods/repos/ 下并命名为master
但是这个方法给了我启发，下载包放到那里后，使用pod search AFNetworking能搜到东西了，但是在项目里使用pod install 还是会出错
错误如下：
[!] Unable to add a source with url `https://github.com/CocoaPods/Specs.git` named `master-1`.
You can try adding it manually in `~/.cocoapods/repos` or via `pod repo add`.
然后我就纳闷了，~/.cocoapods/repos 目录下不是有一个master了吗？为什么还要添加一个 master-1 ？ 然后我想肯定是下载的那个包有问题，原因是下载的包里没有git文件！
然后我就想明白了！于是直接到~/.cocoapods/repos 目录下执行
git clone https://github.com/CocoaPods/Specs.git 然后就等吧，这时要网好，等下载完成后，把下载下的文件夹的名字改为master
然后在项目里就能使用pod install 安装想要的包了
结果运行 pod install 的时候又出问题了，崩溃啊
Address$ pod install
From https://github.com/CocoaPods/Specs
a4f097d..43b2172master-> origin/master
error: Your local changes to the following files would be overwritten by merge:
Specs/5/f/3/TypeWriting/0.0.1/TypeWriting.podspec.json
Specs/6/6/2/EmptyKit/3.0.0/EmptyKit.podspec.json
Specs/f/0/4/TangramKit/1.0.0/TangramKit.podspec.json
Please commit your changes or stash them before you merge.
Aborting
Updating a4f097d..43b2172
[!] Unable to add a source with url `https://github.com/CocoaPods/Specs.git` named `master-1`.
You can try adding it manually in `~/.cocoapods/repos` or via `pod repo add`.
就是说有几个文件改动了，pod install 会拉取cocoapods的更新，然后本地的会被覆盖，所以执行不了
到这就简单了，到 ~/.cocoapods/repos/master下执行 git reset HEAD --hard
然后再到项目目录下运行pod install 就没问题了！
