Better error handling

#12

Release 0.1.0

First release when Traker's CLI was introduced.

1. Traker CLI and traker list command #7
2. Config file's validation and spec #6
3. specs and bugfixes

First release

First release with very basic set of features:

1. .traker.yml file that keeps track of rake tasks that have to be run in a particular environment
2. Rake tasks executions are logged in specific table in the database