Use 'bcrypt' instead of 'bcrypt-ruby'
Add is_draft column to articles model

This column keeps track of whether the article is still in the drafting phase.
Is so, the article is not published.
Use flash[:notice] instead of `notice: "foobar"` as arguments
Fix HTML

Move </td> tag at incorrect position, remove unnecessary </h3> tag.
Add blank lines in HTML for readability