Rewrite gon data passing

Assigning gon an instance of a custom class leads to making it use the
to_json method for conversion. The disadvantage is that the class
name maps then to a hash of attributes and their values.

For convenience I map the objects to hashes containing only the
attributes and their values without the class name as key.

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

The select form on the metrics dashboard was still without function. I
have added a helper function to determine the current repository which
sets the selected attributed of the option.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Filter metadata by repository for computation

Until now the metrics were applied to all metadata. I have added a
repository filter to the ElasticSearch query.

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

I plan to store the repositorie metric scores in the repository objects.
Each metric has its own object containing minimum, average, median and
maximum score.

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

I plan to store the repository metric scores in the repository objects.
Each metric has its own object containing minimum, average, median and
maximum score.

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