use builds.sr.ht instead of travis

.build.yml

@@ -0,0 +1,18 @@
+arch: null
+artifacts: []
+environment: {}
+image: nixos/20.09
+packages: []
+repositories:
+  nixpkgs: https://github.com/NixOS/nixpkgs/archive/nixos-20.09.tar.gz
+secrets: []
+shell: false
+sources:
+- https://github.com/bsima/urbit-airlock
+tasks:
+- build: |
+    export NIXPKGS_ALLOW_BROKEN=1
+    cd urbit-airlock
+    nix-build
+# - test: nix-shell --command "runghc ./test.hs"
+triggers: []

.travis.yml

@@ -1,27 +0,0 @@
-language: nix
-os: linux
-dist: xenial
-# 'vm' means use the full VM, which has 7.5G memory, instead of an LXD
-# container which has "~4G"
-virt: vm
-before_script:
-  # get more swap
-  - sudo fallocate -l 4G /swapfile
-  - 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
-  - install ./urbit-v0.10.8-linux64/urbit ~/bin
-  - export PATH=~/bin:$PATH
-  - export PORT=8080
-  # start urbit daemon
-  - ./fakezod.sh -d
-script:
-  - nix-build
-  - nix-shell --run "runghc ./test.hs"
-after_script:
-  # kill the urbit daemon
-  - ps aux|grep "\-dF zod"|grep -v grep|tr -s " "|cut -f2 -d" "|xargs kill -9