title: Golang mapstructure not working as expected
body: <p>I am trying to decode a <code>map[string]interface{}</code> to a struct, but the "hours" field is not getting populated. I am using <a href="https://github.com/mitchellh/mapstructure" rel="nofollow noreferrer">https://github.com/mitchellh/mapstructure</a> for decoding. This is the struct: </p>
  
  <pre><code>BusinessAddRequest struct {
          Name       string `json:"name"`
          Phone      string `json:"phone"`
          Website    string `json:"website,omitempty"`
          Street     string `json:"street"`
          City       string `json:"city"`
          PostalCode string `json:"postalCode"`
          State      string `json:"state"`
          Hours []struct {
              Day                 string `json:"day"`
              OpenTimeSessionOne  string `json:"open_time_session_one,omitempty"`
              CloseTimeSessionOne string `json:"close_time_session_one,omitempty"`
              OpenTimeSessionTwo  string `json:"open_time_session_two,omitempty"`
              CloseTimeSessionTwo string `json:"close_time_session_two,omitempty"`
          } `json:"hours"`
          Cuisine []string `json:"cuisine,omitempty"`
          BusinessID int `json:"businessId,omitempty"`
          AddressID  int `json:"addressId,omitempty"`
          UserID     int `json:"userId,omitempty"`
  }
  </code></pre>
  
  <p>And this is the example data:</p>
  
  <pre><code>{
      "name": "Agave ...",
      "phone": "(408) 000-000",
      "street": "Abcd",
      "city": "San",
      "postalCode": "90000",
      "state": "CA",
      "hours": [
        {
          "day": "monday",
          "open_time_session_one": "10:00",
          "close_time_session_one": "21:00"
        }
      ],
      "cuisine": [
        "Mexican, tacos, drinks"
      ],
      "userId": 1
  }
  </code></pre>
  
  <p>All fields are getting populated except "hours".</p>