Add methods to resolve diff notes and discussions

app/models/diff_note.rb

@@ -85,6 +85,24 @@ class DiffNote < Note
     self.resolved_at.present?
   end
 
+  def resolve!(current_user)
+    return unless resolvable?
+    return if resolved?
+
+    self.resolved_at = Time.now
+    self.resolved_by = current_user
+    save!
+  end
+
+  def unresolve!
+    return unless resolvable?
+    return unless resolved?
+
+    self.resolved_at = nil
+    self.resolved_by = nil
+    save!
+  end
+
   private
 
   def supported?

app/models/discussion.rb

@@ -63,6 +63,18 @@ class Discussion
     notes.any?(&:to_be_resolved?)
   end
 
+  def resolve!(current_user)
+    notes.each do |note|
+      note.resolve!(current_user) if note.resolvable?
+    end
+  end
+
+  def unresolve!
+    notes.each do |note|
+      note.unresolve! if note.resolvable?
+    end
+  end
+
   def for_target?(target)
     self.noteable == target && !diff_discussion?
   end