日志终端：
user@c6b65b118139:/projects/rails-jafar$ gem install pg Building native extensions. This could take a while... ERROR: Error installing pg: ERROR: Failed to build gem native extension. current directory: /usr/local/bundle/gems/pg-1.1.4/ext /usr/local/bin/ruby -r ./siteconf20190831-425-ife1vi.rb extconf.rb checking for pg_config... no No pg_config... trying anyway. If building fails, please try again with --with-pg-config=/path/to/pg_config checking for libpq-fe.h... no Can't find the 'libpq-fe.h header *** 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.
apt-get install libmysqlclient-dev
libmysqlclient-dev E： 无法打开锁定文件/var/lib/dpkg/lock - 打开(13：权限被拒绝( E：无法锁定管理 目录 (/var/lib/dpkg/(，你是 root 吗？
goorm.io 我用安装 libpq-dev 解决
apt-get install libpq-dev
sudo apt-get update
sudo apt-get install mysql-client libmysqlclient-dev
gem install mysql2