Solve 'using password on command line' warning

[sauloperez]

We need to solve the warning below when executing the test suite:

(...)
    when index is set to true
Warning: Using a password on the command line interface can be insecure.
Warning: Using a password on the command line interface can be insecure.
Warning: Using a password on the command line interface can be insecure.
        adds an index for the reference column
(...)

we might need to specify the password of the testing database in a config file.

[sauloperez]

d17d599 might do the trick. We still need to investigate.

[jamesmacwilliam]

I'm not able to reproduce this bug, using ruby 2.4.4 and RSpec 3.8 after running bin/setup and rake spec