Improving the deprecation warning, making the message optional arg

It was hard for me to switch to the new methods, improved the deprecation warning by telling what method needs to be changed to the new name.

lib/light-service/context.rb

@@ -46,26 +46,26 @@ def skip_all?
     end
 
     def set_success!(message)
-      warn 'DEPRECATED: Please use `succeed!` instead'
+      warn '`set_success!` is DEPRECATED: please use `succeed!` instead'
       succeed!(message)
     end
 
-    def succeed!(message)
+    def succeed!(message=nil)
       @message = message
       @outcome = ::LightService::Outcomes::SUCCESS
     end
 
     def set_failure!(message)
-      warn 'DEPRECATED: Please use `fail!` instead'
+      warn '`set_failure!` is DEPRECATED: please use `fail!` instead'
       fail!(message)
     end
 
-    def fail!(message)
+    def fail!(message=nil)
       @message = message
       @outcome = ::LightService::Outcomes::FAILURE
     end
 
-    def skip_all!(message = nil)
+    def skip_all!(message=nil)
       @message = message
       @skip_all = true
     end

spec/context_spec.rb

@@ -53,12 +53,26 @@ module LightService
       expect(context).to be_success
     end
 
+    it "can be pushed into a SUCCESS state without a message" do
+      context = Context.make
+      context.succeed!
+      expect(context).to be_success
+      expect(context.message).to be_nil
+    end
+
     it "can be pushed into a FAILURE state" do
       context = Context.make
       context.fail!("a sad end")
       expect(context).to be_failure
     end
 
+    it "can be pushed into a FAILURE state without a message" do
+      context = Context.make
+      context.fail!
+      expect(context).to be_failure
+      expect(context.message).to be_nil
+    end
+
     it "can set a flag to skip all subsequent actions" do
       context = Context.make
       context.skip_all!