Added "customers" as an attribute of Organizations

We recently added sources to the Knowledge Graph that provide insights into 'service provider <> customer' relationships. The 'customer' attribute is populated for over 50k companies. Here is an example of a customer of IBM's represented in JSON:

"customers": [
  {
    "summary": "Major airline of the United States",
    "image": "https://kg.diffbot.com/image/api/get?fetch=yes&url=g%3Cj7P0St0DnBJf.x0KwLZrUn.%5B%3CR0Aa4Hh%3B%5Bv738ZqOr7U%3FivHo%3Ef%5B1_l%2F%5B9%40%3BAk%7BAt%3C%60e%5Bt%3DH%2FDk%7DO%28YpOr%29.oCJ",
    "types": [
      "Organization",
      "Corporation"
    ],
    "name": "American Airlines",
    "diffbotUri": "http://diffbot.com/entity/ECm88VZ0TMyq8glAXFBMYaA",
    "targetDiffbotUri": "http://diffbot.com/entity/ECm88VZ0TMyq8glAXFBMYaA",
    "targetDiffbotId": "ECm88VZ0TMyq8glAXFBMYaA",
    "surfaceForm": "American Airlines",
    "type": "Corporation"
  },
  {
    "summary": "Telecommunications company",
    "image": "https://kg.diffbot.com/image/api/get?fetch=yes&url=g%3Cj7P0St0DnBJf.x0KwLZrUn.%5B%3CR0Aa4Hh%3B%5Bv738ZqOr7U%3FDvsR%3EgB%7BYr3izczY2.K%7C%3E",
    "types": [
    "Organization",
    "Corporation"
    ],
    "name": "BT Italia",
    "diffbotUri": "http://diffbot.com/entity/EZK7tKHZCNGCUhTjGW7SaKg",
    "targetDiffbotUri": "http://diffbot.com/entity/EZK7tKHZCNGCUhTjGW7SaKg",
    "targetDiffbotId": "EZK7tKHZCNGCUhTjGW7SaKg",
    "surfaceForm": "BT Italia",
    "type": "Corporation"
  },
  ...
]

We will continue to scale up coverage over time.