diff --git a/.gitignore b/.gitignore
index 2211df6..1103905 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 *.txt
+dist/
+dist-newstyle/
diff --git a/koodihaaste.cabal b/koodihaaste.cabal
index 2ba2220..f96aa23 100644
--- a/koodihaaste.cabal
+++ b/koodihaaste.cabal
@@ -19,7 +19,9 @@ extra-source-files:  CHANGELOG.md
 
 executable koodihaaste
   main-is:             Main.hs
-  -- other-modules:
+  other-modules:       Data.Language
+                     , Data.NGram
+                     , Data.Caesar
   -- other-extensions:
   build-depends:       base >=4.12 && <4.13
                      , servant
diff --git a/release.nix b/release.nix
index 48b1285..3d706e5 100644
--- a/release.nix
+++ b/release.nix
@@ -12,6 +12,7 @@ rec {
     buildInputs = with pkgs.haskellPackages; [
       ghcid
       hlint
+      cabal-install
       (ghcWithHoogle (h: koodihaaste.buildInputs ++ koodihaaste.propagatedBuildInputs))
     ];
   };
diff --git a/src/Data/Caesar.hs b/src/Data/Caesar.hs
new file mode 100644
index 0000000..6956edb
--- /dev/null
+++ b/src/Data/Caesar.hs
@@ -0,0 +1 @@
+module Data.Caesar where
diff --git a/src/Data/Language.hs b/src/Data/Language.hs
new file mode 100644
index 0000000..dde92a5
--- /dev/null
+++ b/src/Data/Language.hs
@@ -0,0 +1 @@
+module Data.Language where
diff --git a/src/Data/NGram.hs b/src/Data/NGram.hs
new file mode 100644
index 0000000..19d7351
--- /dev/null
+++ b/src/Data/NGram.hs
@@ -0,0 +1 @@
+module Data.NGram where