Add fileExtension config for md files

config.dhall

@@ -2,6 +2,7 @@
 , postsOutputPath = "posts"
 , startDate = 1959-01-15
 , seed = +2016
+, fileExtension = "md"
 , adjectives1 =
   [ "absorbing"
   , "adorable"

generateSealPosts.hs

@@ -30,6 +30,7 @@ import           System.Random      (Random (randoms), mkStdGen)
 data Config = Config
   { adjectives1     :: [Text]
   , adjectives2     :: [Text]
+  , fileExtension   :: String
   , looks           :: [Text]
   , sealImagesPath  :: FilePath
   , postsOutputPath :: FilePath
@@ -102,11 +103,12 @@ sealText config n rand date = ( fileName', bp )
          show date <> "-"
       <> "seal-post-"
       <> show n
-      <> ".markdown"
+      <> "." <> fileExtension'
     date'     = T.pack . show $ date
     title     = T.pack $ "Seal Post Number " <> show n
     title'    = T.replace " " "-" title
     sealImagesPath' = sealImagesPath config
+    fileExtension' = fileExtension config
 
     bp = blogPost' (toGregorian date)