title: Can't decode data from a yml file
body: <p>I want to read some basic settings from a yml file. Here's my attempt:</p>
  
  <pre><code>  #config.yml 
    some_value: "fdsfdsfd"
  
  
    #.hs
    yamlData &lt;- BS.readFile "./config.yml"
    let var1 = Data.Yaml.decode yamlData :: Maybe String
    print $ "the key is " ++ fromJust var1
  </code></pre>
  
  <p>It returns <code>Maybe.fromJust: Nothing</code>. Should I necessarily create a <code>data</code> from <code>some_value</code> and implement <code>FromJSON</code> and <code>ToJSON</code> for it even if, like in my case, it's only one <code>String</code> field? Or is the issue somewhere else in my code?</p>