title: Add missing hashes from one Array into another
body: <p>I have two ruby Arrays. The source_array contains all my source data in form of hashes. I have a user_array that contains a subset of data that a user has selected. I need to merge/combine the two arrays to form a new result_array keeping all the hashes from the user_array and adding those hashes from the source_array that does not exist in the user_array.</p>
  
  <p>Source Array:</p>
  
  <pre><code>   source_array = [ 
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F150", :notes=&gt;""}, 
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F250", :notes=&gt;""}, 
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F350", :notes=&gt;""},
        {:category=&gt;"truck", :make=&gt;"chevy", :model=&gt;"Silverado 1500", :notes=&gt;""}
      ]
  </code></pre>
  
  <p>Target Array:</p>
  
  <pre><code>target_array = [ 
    {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F150", :notes=&gt;"Mileage 290 miles for a full tank of gas. Shortlist for now."}
  ]
  </code></pre>
  
  <p>Result Array:</p>
  
  <pre><code>result_array = [ 
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F150", :notes=&gt;""}, 
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F250", :notes=&gt;""}, 
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F350", :notes=&gt;""},
        {:category=&gt;"truck", :make=&gt;"ford", :model=&gt;"F150", :notes=&gt;"Mileage 290 miles for a full tank of gas. Shortlist for now."}
      ]
  </code></pre>
  
  <p>I appreciate any help you can provide!</p>