Add Annotations and Modifiers page (#34)

* Create AnnotationsAndModifiers.md

* Update README.md

* Update AnnotationsAndModifiers.md

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AnnotationsAndModifiers.md

@@ -0,0 +1,51 @@
+# Annotations and Modifiers
+
+## Convention
+
+Method/variable annotations and modifiers should go on the _same_ line as the rest of the definition. i.e.
+
+## Rationale
+
+Consistency makes PRs easier to read as well as removing any potential disagreements. 
+
+## Annotations
+
+
+```swift
+// good: On the same line
+@objc func doThing() { }
+
+// bad: Not on the same line
+@objc
+func doThing() { }
+```
+
+There is an exception for when you are renaming for Objective-C. In that case, the annotation _may_ go on the preceeding line. e.g.
+
+```swift
+@objc(XYThing)
+enum Thing: Int {
+...
+}
+```
+
+The ordering for the annotations follows [that of SwiftLint](https://realm.github.io/SwiftLint/modifier_order.html). i.e. `@objc`, `@nonobjc`, `@objcMembers`, `@IBAction`, `@IBOutlet`, `@IBDesignable`, `IBInspectable`, `@NSManaged`, `@NSCopying`
+
+
+## Modifiers
+
+Similarly, modifiers should go on the same line and follow SwiftLint conventions for order. e.g.
+
+Regarding the ordering of the annotations, we again follow SwiftLint. i.e. The order should be:
+
+* `override` - Specify if this is an override or not
+* Access level (e.g. `private`, `public`, `open`, etc.)
+* Setter access level
+* `dynamic` - Specify if dynamic dispatch should be used
+* Mutators - `mutating` or `nonmutating`
+* `lazy` - Specify if this declaration is lazy or not
+* `final` - Specify if this declaration is final
+* `required` - Specify if an initializer is required or not
+* `convenience` - Specify if a declaration as convenient or not
+* `static` - Specify if this is static or not <!-- Swiftlint refers to these as "type methods" but I can't think of any alternatives to static that would be left? -->
+* `weak` - Specify if the ownership is weak or not

README.md

@@ -8,6 +8,7 @@ The Swift coding conventions guide documents many best practices for writing Swi
 
 # Table of Contents
 
+* [Annotations and Modifiers](AnnotationsAndModifiers.md)
 * [Comments](Comments.md)
 * [Delegates](Delegates.md)
 * [Early Return](EarlyReturn.md)