Fixes issue with category and guides

Guides were not displaying because of a missing ‘,’ in the meta tag
information in the guides view. Added a helper to generate the meta_tag
options

Also fixed and issue where the categories were not linking to the
correct article urls.

Gave the category factory a more proper title using Faker.
Merge pull request #17 from 18F/feature/fix_categories_article_list

Fixes #29 + #30 - issues with guide views