Implement repository overview

I have updated the repository model class and implemented a controller
which simply fetches the data from the ElasticSearch database. The view
displays the repository records in a table.

In addition, I have added pry support to the Gemfile for making the
Rails application debuggable.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Transform repository URL to actual hyperlinks

Just added an a-tag to the repository rendering. Also included a regular
expression for removing http/https and www whem displaying the link.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Renamed CKAN metadatum class and added super class

The metadatum class was actually a CKAN metadatum class, so for
convenience I have renamed the class. For future generalization
I have also added a super class metadatum.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Delete generated RSpec helpers for now

Currently, I do not plan to implement code in the controller helper
classes. Hence, I have removed the RSpec helper files in order to
address the RSpec warnings.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Write basic views test

I have filled the generated view test files with some content. Although
not very specific yet.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Write completeness metric test and implementation

The first metric has been added is the completeness metric which counts
the number of fields and number of completed fields for a given dataset.
For now the test should suffice.

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