EmotionAll MVP

Users can choose from a list of trends in our database and see a heat map of the world based on the sentiment of tweets for that particular trend. 
This might be a bit nicer/more Railsy like:

```ruby
  existing_trend = Trend.find_or_initialize_by(name: trend.name)
  existing_trend.updated_at = Time.now unless existing_trend.new_record?
  existing_trend.woeid = woeid if existing_trend.new_record?
  existing_trend.save
```