allow simultaneously searching on both tsvector & non-tsvector columns

[ajb]

Opening this again, tests included this time. (#126 was the old PR)

@nertzy would appreciate you taking a look when you get a chance :). Happy holidays! 🎅

[ajb]

there's gotta be better variable name than return_str...

[nertzy]

A better approach would be to create an array of expressions and then only do the .join(" || ") part at the very end.

[coveralls]

Coverage remained the same when pulling 011c78c on adamjacobbecker:from-upstream into c10704a on Casecommons:master.

[nertzy]

I'm a bit wary of merging this in. I think I need to better understand your use case.

For one thing, you're changing the current behavior of how :against and :tsvector_column interact, which would be a breaking change for existing users. For example, this valid search scope would now behave differently:

pg_search_scope :search_content,
  :against => "title",
  :using => {
    :tsearch => {
      :tsvector_column => "title_tsvector"
    },
    :trigram => {},
    :dmetaphone => {}
  }

In your implementation, I'm not sure how it would be possible to tell :trigram and :dmetaphone to search against title while having :tsearch only search against tsvector_title.

Also, I want to understand why you need to mix the two column types together. I feel like the most common case for using :tsvector_column is to write a database trigger that keeps the tsvector column up-to-date with all searchable content on every insert, like it's described in http://www.postgresql.org/docs/current/static/textsearch-features.html#TEXTSEARCH-UPDATE-TRIGGERS

Let me know if that solution doesn't work for your particular use case, so that we can figure out how best to make pg_search work for you. For now, I'm closing this pull request. Feel free to reopen it if there's something I've misunderstood.