add Nix files

.gitignore

@@ -1,3 +1,5 @@
+/result
+
 /src/*.erl
 
 tags

default.nix

@@ -0,0 +1,8 @@
+{ nixpkgs ? import <nixpkgs> }:
+
+let pkgs = nixpkgs {
+  overlays = [ (self: super: {
+    paddle = self.callPackage ./derivation.nix {};
+  }) ];
+};
+in pkgs.paddle

derivation.nix

@@ -0,0 +1,39 @@
+{ stdenv, beamPackages, openldap }:
+
+beamPackages.buildMix {
+  name = "paddle";
+  version = "0.1.5";
+
+  src = ./.;
+
+  checkInputs = [ openldap ];
+
+  patchPhase = ''
+    substituteInPlace .travis/ldap/slapd.conf \
+      --replace /etc/ldap ${openldap}/etc \
+      --replace /usr/lib/openldap ${openldap}/lib
+
+    cp config/dev.exs config/prod.exs
+
+    substituteInPlace config/test.exs \
+      --replace /etc/ldap ${openldap}/etc
+  '';
+
+  checkPhase = ''
+    mkdir /tmp/slapd
+    ${openldap}/libexec/slapd -d2 -f .travis/ldap/slapd.conf -h ldap://localhost:3389 &
+    sleep 3
+    ldapadd -h localhost:3389 -D cn=admin,dc=test,dc=com -w test -f $src/.travis/ldap/base.ldif
+    ldapadd -h localhost:3389 -D cn=admin,dc=test,dc=com -w test -f $src/.travis/ldap/test_data.ldif
+
+    MIX_ENV=test mix test
+  '';
+
+  doCheck = true;
+
+  meta = with stdenv.lib; {
+    description = "A library simplifying LDAP usage in Elixir projects";
+    homepage = "https://github.com/minijackson/paddle";
+    license = licenses.mit;
+  };
+}