Vendor swiftenv installation script

.travis.yml

@@ -4,8 +4,8 @@ language: generic
 sudo: required
 dist: trusty
 env:
-  - SWIFT_VERSION=5.0
+  - SWIFT_VERSION=5.0 SWIFTENV_ROOT="$HOME/.swiftenv" PATH="$SWIFTENV_ROOT/bin:$SWIFTENV_ROOT/shims:$PATH"
 install:
-  - eval "$(curl -sL https://swiftenv.fuller.li/install.sh)"
+  - ./scripts/install_swiftenv.sh
 script:
   - swift build

scripts/install_swiftenv.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# Automatically installs swiftenv and run's swiftenv install.
+# This script was designed for usage in CI systems.
+
+git clone --depth 1 https://github.com/kylef/swiftenv.git ~/.swiftenv
+export SWIFTENV_ROOT="$HOME/.swiftenv"
+export PATH="$SWIFTENV_ROOT/bin:$SWIFTENV_ROOT/shims:$PATH"
+
+if [ -f ".swift-version" ] || [ -n "$SWIFT_VERSION" ]; then
+  swiftenv install -s
+else
+  swiftenv rehash
+fi
+