Add library specification to cabal file

Main.hs

@@ -10,4 +10,9 @@ space :: ToroidalSpace Bool
 space = tabulate (\(x, y) -> (x + y `mod` 5) * 10 + x - y > 30)
 
 main :: IO ()
-main = playYampa (InWindow "a" (200, 200) (10, 10)) black 30 (run space)
+main =
+  playYampa
+    (InWindow "Conway's Game of Life" (200, 200) (10, 10))
+    black
+    30
+    (run space)

conways-game-of-life.cabal

@@ -6,6 +6,16 @@ license:        MIT
 build-type:     Simple
 cabal-version:  >= 1.8
 
+library
+  build-depends:    base,
+                    vector,
+                    comonad,
+                    distributive,
+                    adjunctions
+  exposed-modules:  GOL.Rule,
+                    GOL.Space,
+                    GOL.Engine
+
 executable gol
   main-is:        Main.hs
   other-modules:  GOL.Rule,