position_in_ should accept a string as well as a symbol

lib/annotate/annotate_models.rb

@@ -142,7 +142,8 @@ module AnnotateModels
           new_content = old_content.sub(/^# #{COMPAT_PREFIX}.*?\n(#.*\n)*\n/, info_block)
           # But, if there *was* no old schema info, we simply need to insert it
           if new_content == old_content
-            new_content = options[:position] == :before ?
+            position = options[:position] || :before
+            new_content = position.to_sym == :before ?
               (info_block + old_content) :
               ((old_content =~ /\n$/ ? old_content : old_content + '\n') + info_block)
           end