Add ContextTitleView doc

Author: mukeshthawani

Documentation/ContextTitleView.md

@@ -0,0 +1,51 @@
+## ContextTitleView
+
+This article will guide you how to subclass the `ALKContextTitleView` class and customize it according to your requirements.
+
+![simulator screen shot context title view ](https://user-images.githubusercontent.com/5956714/35631016-cefd93e6-06c8-11e8-9b7e-803850f6c4a7.png)
+
+### Subclass and Modify the UI
+
+```swift
+
+class TitleContextView: ALKContextTitleView {
+
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+    }
+
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override func setupUI() {
+        super.setupUI()
+        titleLabel.isHidden = true
+        titleLabel.backgroundColor = UIColor.black
+    }
+}
+```
+
+
+### Inject the Subclassed view
+
+```swift
+
+class ConversationVC: ALKConversationViewController {
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        let view = TitleContextView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
+        self.contextTitleView = view
+    }
+}
+
+class ConversationListVC: ALKConversationListViewController {
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        conversationViewController = ConversationVC()
+
+    }
+}
+
+```