run on Travis CI container infra

.travis.yml

@@ -1,4 +1,5 @@
 language: rust
+sudo: false
 install:
   - .travis/docs/install
 script: 

.travis/docs/after_success

@@ -1,5 +1,6 @@
 #!/bin/bash
 set -e
+export PATH="$HOME/.local/bin:$PATH"
 
 if [ "$TRAVIS_PULL_REQUEST" = false ] && [ "$TRAVIS_BRANCH" = master ]; then
   echo '<meta http-equiv="refresh" content="0;url=fringe/">' > target/doc/index.html

.travis/docs/install

@@ -2,5 +2,5 @@
 set -e
 
 if [ "$TRAVIS_PULL_REQUEST" = false ] && [ "$TRAVIS_BRANCH" = master ]; then
-  sudo pip install ghp-import
+  pip install --user ghp-import
 fi