title: MongoDB in Go (golang) with mgo: how to use logical operators to query?
body: <p>I would like to run the following query in golang using mgo in a pipeline.</p>
  
  <pre><code>{"key1" : 1,
   "$or" : [{"key2" : 2}, {"key3" : 2}]}
  </code></pre>
  
  <p>I have looked everywhere, but I cannot find an example like this. I have tried many different combinations, for example:</p>
  
  <pre><code>...
  pipeline := []bson.M{
                       bson.M{    "$match" :  bson.M{ "key1" : 1,  
                                                     "$or" : bson.M{ "key2" : 2, "key3" : 2},
                       }
                       ...
              }
  </code></pre>
  
  <p>which compiles correctly, does not find anything. Any ideas?</p>
  
  <p>Thank you in advance</p>