title: PG::UndefinedFunction: ERROR: operator does not exist: geometry && box
body: <p>Why does PostgreSQL complain that the <code>&amp;&amp;</code> operator does not exist? (I have PostGIS installed - see below).</p>
  
  <pre><code>mydb=# SELECT "monuments".* FROM "monuments" WHERE
  mydb=# (coord &amp;&amp; '-10,-10,10,10'::box)
  mydb=# ORDER BY created_at DESC ;
  ERROR:  operator does not exist: geometry &amp;&amp; box
  LINE 1: ...LECT "monuments".* FROM "monuments" WHERE (coord &amp;&amp; '-10...
                                                               ^
  HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.
  </code></pre>
  
  <p>I have PostGIS installed:</p>
  
  <pre><code>mydb=# select postgis_full_version();
  NOTICE:  Function postgis_topology_scripts_installed() not found. Is topology support enabled and topology.sql installed?
                                                                        postgis_full_version                                                                      
  ----------------------------------------------------------------------------------------------------------------------------------------------------------------
   POSTGIS="2.1.0 r11822" GEOS="3.3.8-CAPI-1.7.8" PROJ="Rel. 4.8.0, 6 March 2012" GDAL="GDAL 1.10.0, released 2013/04/24" LIBXML="2.9.1" LIBJSON="UNKNOWN" RASTER
  </code></pre>
  
  <p>And by the way, my table looks like this:</p>
  
  <pre><code>mydb=# \d monuments
   id    | integer              | not null default nextval('monuments_id_seq'::regclass)
   coord | geometry(Point,3785) |
  </code></pre>
  
  <p>Let me know if you need any more info.</p>