Automatically build book and deploy to a repo (#284)

* Use Travis to test building the book.

* Add script to deploy the book to a separate repo.

* Make messages bold; fix duplicate word

Author: berquist

.travis.yml

@@ -0,0 +1,24 @@
+dist: trusty
+sudo: false
+
+language: node_js
+node_js:
+  - "4"
+
+cache:
+  directories:
+    - node_modules
+
+install:
+  - npm install gitbook-cli -g
+  - gitbook install
+
+before_script:
+  - mkdir -p "${TRAVIS_BUILD_DIR}"/build
+
+script:
+  - gitbook build . "${TRAVIS_BUILD_DIR}"/build
+  - |
+    if [[ "${TRAVIS_BRANCH}" == master ]]; then
+        bash "${TRAVIS_BUILD_DIR}"/tools/deploy/update_site_travis.bash
+    fi

tools/deploy/update_site_travis.bash

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+
+# update_site_travis.bash: Update a GitHub repo with the book build
+# products.
+
+set -o errexit
+
+# Required environment variables:
+# - DOCS_BRANCH_NAME: name of the remote branch serving the book
+# - GH_REPO_NAME: name of the remote repo
+# - GH_TOKEN: [secret] Personal Access Token
+# - GH_USER: name of the remote repo's owner
+
+bold=$(tput bold)
+normal=$(tput sgr0)
+
+if [ -z ${DOCS_BRANCH_NAME+x} ]; then
+    echo "${bold}\$DOCS_BRANCH_NAME is not set!${normal}"
+    exit 1
+elif [ -z ${GH_REPO_NAME+x} ]; then
+    echo "${bold}\$GH_REPO_NAME is not set!${normal}"
+    exit 1
+elif [ -z ${GH_TOKEN+x} ]; then
+    echo "${bold}\$GH_TOKEN is not set!${normal}"
+    exit 1
+elif [ -z ${GH_USER+x} ]; then
+    echo "${bold}\$GH_USER is not set!${normal}"
+    exit 1
+fi
+
+git config user.name "Travis CI User"
+git config user.email "travis@travis-ci.org"
+
+GH_REPO_REF="github.com/${GH_USER}/${GH_REPO_NAME}.git"
+
+# Assume the book has already been built, and was moved to `build/`
+# inside the same directory as this script.
+
+if [ -d build ]; then
+    echo "${bold}Cloning the website repo...${normal}"
+    git clone -b $DOCS_BRANCH_NAME https://git@${GH_REPO_REF}
+    rm -rf ./"${GH_REPO_NAME}"/*
+    cp -a ./build/* ./"${GH_REPO_NAME}"
+    pushd ./"${GH_REPO_NAME}"
+    echo "${bold}Adding changes...${normal}"
+    git add --all
+    echo "${bold}Committing...${normal}"
+    # This will return 1 if there are no changes, which should not
+    # result in failure.
+    git commit \
+        -m "Deploy book to GitHub Pages Travis build: ${TRAVIS_BUILD_NUMBER}" \
+        -m "Commit: ${TRAVIS_COMMIT}" || ret=$?
+    git push --force "https://${GH_TOKEN}@${GH_REPO_REF}" > /dev/null 2>&1
+    popd
+else
+    echo "" >&2
+    echo "${bold}Warning: The book wasn't found!${normal}" >&2
+    echo "${bold}Warning: Not going to push the book to GitHub!${normal}" >&2
+    exit 1
+fi