Revert "Run boostrap:themed generator for article"

This reverts commit f5e9fd58c0cf093e34d2e5fce53f5e34676e162f.

Used singular for bootstrap:themed generator. Needs to be plural of
model.
Run boostrap:themed generator for articles again.

Already did this before, but used singular of article instead of plural. But generator needs plural. => "rails g bootstrap:themed Articles"