feat(install): find path to exec automatically

- Will find the path to itself and set path in git hook
- Lets it be run from anywhere in project dir instead of just root

Closes #6

cgtools.cabal

@@ -48,6 +48,7 @@ executable cgtools
                      , bytestring
                      , ansi-terminal
                      , hastache
+                     , FindBin
 
   main-is:             Main.hs
   -- from Tasty cabal with ansi-terminal
@@ -82,6 +83,7 @@ library
                        , bytestring
                        , ansi-terminal
                        , hastache
+                       , FindBin
 
   -- from Tasty cabal with ansi-terminal
   cpp-options: -DCOLORS

src/CGTools/Install.hs

@@ -13,20 +13,22 @@ import Text.Hastache.Context (mkGenericContext)
 import Data.Data (Data, Typeable)
 import Paths_cgtools
 import System.IO (hFlush, stdout)
+import System.Environment.FindBin (getProgPath)
 
 data Ctx = Ctx {
   path :: Text
 } deriving (Data, Typeable)
 
 runInstall :: IO ()
 runInstall = do
+  bin <- getProgPath
+  let binPath = pack $ bin ++ "/cgtools"
+  let context = mkGenericContext Ctx { path =  binPath }
   g <- getGitPath
   let commitHook = getPrepareCommitPath (pack g)
   genFile context "prepare-commit-msg" commitHook
   p <- getPermissions commitHook
   setPermissions commitHook (p {executable = True})
-  where
-    context = mkGenericContext Ctx { path = "./cgtools" }
 
 getGitPath :: IO String
 getGitPath = readProcess "git" [  "rev-parse", "--git-dir" ] ""