Member can now publish multiple distinct articles, with helper.

Cautiously re-trying failed Big Bang as iteration, Step 4 of 4.

FeatureSpecNewPostHelper class can now be used to publish multiple posts
which each have unique content matching a common pattern. This gets us
where the "big bang" from the abandoned breadcrumb would have gotten us
had it succeeded. Yak shave complete!

RSpec: 622 examples, 0 failures
RuboCop: 144 files inspected, no offenses detected