Allow type or coerce to specify coercion type

Author: schmurfy

lib/grape/validations.rb

@@ -95,6 +95,11 @@ def optional(*attrs)
       def validates(attrs, validations)
         doc_attrs = { :required => validations.keys.include?(:presence) }
 
+        # special case (type = coerce)
+        if validations[:type]
+          validations[:coerce] = validations.delete(:type)
+        end
+        
         if coerce_type = validations[:coerce]
           doc_attrs[:type] = coerce_type.to_s
         end