Drop collection instead of database.

[Lewwwk]

Prosed fix for #11 - changed from db.dropDatabase() to db.mongodown.drop()

Description

Simply switches the commands as per the issue.

Motivation and Context

Experienced an unexpected production db deletion. (oops)

How Has This Been Tested?

Erm - would love someone to test as well.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[coveralls]

Coverage increased (+0.03%) to 93.868% when pulling e6489b9 on cleanUpdate into e576d0a on master.