Merge pull request #138 from BartlomiejSkwira/patch-1

Add info to tsvector section about schema_format
Adjust spec's expectation of DateTime precision

https://github.com/Casecommons/pg_search/issues/139
Fix typo (forgot an || operator)
Better explanation of the necessary schema format

Quoting @nertzy with his better explanation and Rails guides link
Merge pull request #140 from BartlomiejSkwira/patch-2

Better explanation of the necessary schema format change
Normalize trigram query and document as Arel nodes

We need to normalize the Trigram's query and document, making sure they
are Arel nodes, not strings so that the
`Arel::Nodes::InfixOperation.new` correctly puts them together with the
'%' operator. Without this change, they are incorrectly escaped as:

```sql
(
  ('unaccent(coalesce("pg_search_documents"."content"::text, ''''))')
  %
  'unaccent(Cambonator Doppelbock)'
)
```

The correct escaping is:

```sql
(
  (unaccent(coalesce("pg_search_documents"."content"::text, '')))
  %
  unaccent('Cambonator Doppelbock')
)

```
Merge pull request #141 from stevenharman/allow_trigrams_and_unaccent_work_together

Normalize trigram query and document as Arel nodes
Add unit tests for Trigram conditions

This also includes a major overhaul of this whole spec file, collapsing
much setup into some `let`s and using an OpenStruct for the config
object.
Require 'ostruct' for Ruby < 2.0
Need rspec >= 2.14 for `expect` syntax
Merge pull request #143 from stevenharman/add_unit_tests_for_trigram_feature

Add unit tests for Trigram conditions
VERSION 0.7.1
Fix spelling of coalesced_columns
Simplify string literal for coalesced_columns
Remove context for base case

We can keep the base case simple and add contexts for special cases
Add :threshold option for tweaking trigram search

Fixes https://github.com/Casecommons/pg_search/issues/115
VERSION 0.7.2
Use require instead of autoload to pull in dependencies
Add unit tests for Configuration::Association
Add unit tests for Configuration::ForeignColumn