Revert pry-byebug version

In order to make the debugging with pry working again I have specified a
certain version to be used.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add skip cases if value is blank

Rails offers the useful object method blank? which allows to check
whether an object is null, contains only whitespaces, false, empty,
etc. Sometimes values like this have to be skipped altogether in order
to avoid invalid null pointer operations.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>