fix build and debug ci

.travis.yml

@@ -10,6 +10,7 @@ before_script:
   - sudo chmod 600 /swapfile
   - sudo mkswap /swapfile
   - sudo swapon /swapfile
+  - free -h
   # get urbit
   - curl -O https://bootstrap.urbit.org/urbit-v0.10.8-linux64.tgz
   - tar xzf urbit-v0.10.8-linux64.tgz

shell.nix

@@ -6,6 +6,7 @@ nixpkgs.mkShell {
     nixpkgs.ormolu.bin
     (nixpkgs.pkgs.haskell.packages.${compiler}.ghcWithPackages (hp: with hp; [
       aeson base bytestring http-streams lens text uuid wai wai-extra wreq
+      io-streams
     ]))
   ];
 }

urbit-airlock.cabal

@@ -22,6 +22,7 @@ library
     aeson,
     bytestring,
     http-streams,
+    io-streams,
     lens,
     text,
     uuid,

urbit-airlock.nix

@@ -1,5 +1,5 @@
 { mkDerivation, aeson, base, bytestring, lens, stdenv, text, wai
-, wai-extra, wreq, uuid
+, wai-extra, wreq, uuid, http-streams, io-streams
 }:
 mkDerivation {
   pname = "urbit-airlock";