ruby on rails 常见配置错误解决

error：in `require': cannot load such file -- sqlite3/sqlite3_native (LoadError)

先删除 Ruby下的D:\Ruby22-x64\lib\ruby\gems\2.2.0\cache目录；
然后在cmd中输入：gem install sqlite3；
最后进入D:\Ruby22-x64\lib\ruby\gems\2.2.0\specifications目录，找到sqlite3-1.3.10-x64-mingw32.gemspec文件，将s.require_paths=["lib"]改成s.require_paths= ["lib/sqlite3_native"]

 error：D:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/execjs-2.6.0/lib/execjs/runtimes `autodetect': Could not find a JavaScript runtime. See https://github.

/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)

实际报错信息都已经给出来了解决链接https://github.com/sstephenson/execjs，在上边的报错信息中
看过后直接安装这个就行了therubyracer
参考该插件的说明：https://github.com/sstephenson/execjs#readme
安装命令
#gem install therubyracer