dump in yaml & unexpected result

[Siratinee Sukachai]

I have a Hash which value is Array of Hashes. And I expected to generate
the yaml like this:

---
Session:
singular: Session
email: Email
password: Password
rememberMe: Remember Me!


But when I use dump method to generate yaml file and the result is:

---
- Session:
- singular: |
Session

- email: |
Email

- password: |
Password

- rememberMe: |
Remember Me!


When I print out my hash on command line, it look like this:

SessionsingularSession
emailEmail
passwordPassword
rememberMeRemember Me!


What do you think? Am I wrong with any steps?
If I need to generate yaml look like above, how can I do?