Have Travis push rustdoc output to GitHub Pages.

.travis.yml

@@ -7,6 +7,19 @@ install:
   - tar xf cargo-nightly-linux.tar.gz
   - sudo ./cargo-nightly/install.sh
 
+  - sudo pip install ghp-import
+
 script:
-  - cargo build --verbose
-  - cargo test --verbose
+  - cargo build
+  - cargo test
+  - rustdoc src/url.rs -L target/deps
+  - echo '<meta http-equiv=refresh content=0;url=url_/index.html">' > doc/index.html
+
+after_success: |
+  [ $TRAVIS_BRANCH = master ] &&
+  [ $TRAVIS_PULL_REQUEST = false ] &&
+  ghp-import -n doc &&
+  git push -fq https://${TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git gh-pages
+
+env:
+  - secure: DoxnyDvhhRocCKtvyRe0Wa4P/zwhEcSH67kSa1f+KMuLzZQqIxFqCGTha2KzKyuymMMVyUC1Is+MWzVjBtAaIHCm07Do/TH9rWijTZx0pWK9bJ8idxzycGTsZJEyzDQbkpGNRsAfygxwP2r+K6VSE6MDg2M6AjnSLzpjWMLqr+s=