Add a rule for defmethod

Author: marknsikora

README.md

@@ -165,6 +165,31 @@ when there are no arguments on the same line as the function name.
   [x] (bar x))
  ```
 
+* <a name="multimethod-dispatch-val-placement"></a>
+ Place the `dispatch-val` of a multimethod on the same line as the
+ function name.
+<sup>[[link](#multimethod-dispatch-val-placement)]</sup>
+
+
+ ```Clojure
+ ;; good
+ (defmethod foo :bar [x] (baz x))
+
+ (defmethod foo :bar
+  [x]
+  (baz x))
+
+ ;; bad
+ (defmethod foo
+  :bar
+  [x]
+  (baz x))
+
+ (defmethod foo
+  :bar [x]
+  (baz x))
+ ```
+
 * <a name="docstring-after-fn-name"></a>
  When adding a docstring – especially to a function using the above form – take
  care to correctly place the docstring after the function name, not after the