vapor部署到heroku报错

报错信息

➜  MyService git:(master) ✗ git push heroku master

Counting objects: 43, done.

Delta compression using up to 8 threads.

Compressing objects: 100% (33/33), done.

Writing objects: 100% (43/43), 11.58 KiB | 2.90 MiB/s, done.

Total 43 (delta 2), reused 0 (delta 0)

remote: Compressing source files... done.

remote: Building source:

remote:

remote: -----> Swift app detected

remote: Cloning into 'swiftenv'...

remote: Swift 3 Heroku Installer

remote: 🔢  Version: 3.1.1

remote: 🖥  Operating System: ubuntu1404

remote: 📦 Installing Swiftenv

remote: Cloning into '/app/.swiftenv'...

remote: 🐦 Installing Swift

remote: Downloading https://swift.org/builds/swift-3.1.1-release/ubuntu1604/swift-3.1.1-RELEASE/swift-3.1.1-RELEASE-ubuntu16.04.tar.gz

remote: /tmp/swiftenv-3.1.1- /tmp/build_cb17ea379ff9bebcfbc59b704bf4d24c

remote:  % Total    % Received % Xferd  Average Speed  Time    Time    Time  Current

remote:                                  Dload  Upload  Total  Spent    Left  Speed

remote: 100  117M  100  117M    0    0  6374k      0  0:00:18  0:00:18 --:--:-- 5794k

remote: /tmp/build_cb17ea379ff9bebcfbc59b704bf4d24c

remote: 3.1.1 has been installed.

remote: ✅  Done

remote: -----> Installing clang-3.7.0

remote: precompile

remote: -----> Building Package ... this will take a while

remote: swift-build: error: Package requires minimum Swift tools version 4.0.0. Current Swift tools version is 3.1.0

remote:  !    Push rejected, failed to compile Swift app.

remote:

remote:  !    Push failed

remote: Verifying deploy...

解决方法在：

在你的vapor工程的根目录下新建.swift-version文件

打开控制台 输入touch .swift-version 新建文件

用编辑器打开文件 open -e .swift-version 输入4.0保存

然后就OK了 因为是属于隐藏文件夹 所以需要手动添加

git add .swift-version

然后编辑

git commit -am "make it better

重新上传。成功

git push heroku master