Refactor shared Aura + Equipment methods into Attachment class

lib/magic/cards/attachment.rb

@@ -0,0 +1,30 @@
+module Magic
+  module Cards
+    class Attachment < Card
+      def resolve!(target:)
+        permanent = super()
+        permanent.attach_to!(target)
+      end
+
+      def power_modification
+        0
+      end
+
+      def toughness_modification
+        0
+      end
+
+      def keyword_grants
+        []
+      end
+
+      def type_grants
+        []
+      end
+
+      def can_activate_ability?(_)
+        true
+      end
+    end
+  end
+end

lib/magic/cards/aura.rb

@@ -1,36 +1,7 @@
 module Magic
   module Cards
-    class Aura < Card
+    class Aura < Attachment
       TYPE_LINE = "Enchantment -- Aura"
-
-      def single_target?
-        true
-      end
-
-      def resolve!(target:)
-        permanent = super()
-        permanent.attach_to!(target)
-      end
-
-      def power_modification
-        0
-      end
-
-      def toughness_modification
-        0
-      end
-
-      def keyword_grants
-        []
-      end
-
-      def type_grants
-        []
-      end
-
-      def can_activate_ability?(_)
-        true
-      end
     end
   end
 end

lib/magic/cards/equipment.rb

@@ -1,6 +1,6 @@
 module Magic
   module Cards
-    class Equipment < Card
+    class Equipment < Attachment
       TYPE_LINE = "Artifact -- Equipment"
 
       def self.equip(equip_cost)
@@ -20,40 +20,6 @@ def resolve!(target:)
           [equip]
         end
       end
-
-      def resolve!(target:)
-        permanent = super()
-        permanent.attach_to!(target)
-      end
-
-      def single_target?
-        true
-      end
-
-      def resolve!(target:)
-        permanent = super()
-        permanent.attach_to!(target)
-      end
-
-      def power_modification
-        0
-      end
-
-      def toughness_modification
-        0
-      end
-
-      def keyword_grants
-        []
-      end
-
-      def type_grants
-        []
-      end
-
-      def can_activate_ability?(_)
-        true
-      end
     end
   end
 end