dbdump
a database dump tool
How to use it?
```bash
$ dbdump -h
Database dump tool 0.1.1
yuchunzhou chunzhou.yu@qq.com
dump the database data to an ordinary file
USAGE:
dbdump [OPTIONS]
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
OPTIONS:
-H, --host database server address [default: 127.0.0.1]
-P, --port database server port [default: 3306]
-k, --kind database kind [default: mysql] [possible values: sqlite, mysql, postgresql]
-u, --user database username
-p, --password database password
-t, --table which database table to be dumped
-d, --database which database contains the dumped table
-f, --format destination file format [default: csv] [possible values: csv, xls, txt]
-n, --rows how many rows to be dumped [default: 10]
-o, --output