安装Postgres
1) This is the easiest part, simply
$ brew install postgres
2) this step is not obvious but you can’t move on without it (would be nice if brew can automate this step too :D)
$ initdb /usr/local/var/postgres
启动server
pg_ctl -D /user/local/var/postgres start
创建DB
createdb mydb
进入DB
psql mydb user_name (username 是在init 那步的是会提示,一般就是当前机器的登陆用户名)