`rescue in establish_connection': Please install the mysql2 adapter: `gem install activerecord-mysql2-adapter` (no such file to load -- active_record/connection_adapters/mysql2_adapter) (RuntimeError)メモ書き。適当にこんなんやってたら動い…

/usr/local/rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/completion.rb:9:in `require': no such file to load -- readline (LoadError) sudo yum install readline-devel cd /usr/local/rvm/src/ruby-1.9.2-p180/ext/readline ruby extconf.rb make make…