Merge pull request #60 from rafamvc/master

deprecated Image.from_file was still used in the README

Author: HamptonMakes

README.rdoc

@@ -64,7 +64,7 @@ Need to combine several options?
 
 Want to composite two images? Super easy! (Aka, put a watermark on!)
 
-  image = Image.from_file("original.png")
+  image = Image.open("original.png")
   result = image.composite(Image.open("watermark.png", "jpg") do |c|
     c.gravity "center"
   end