Add website_config back without CSP

Author: XAMPPRocky

.travis.yml

@@ -19,6 +19,7 @@ before_script:
   - mdbook -V || cargo install mdbook --vers '^0.3.0'
 script:
   - mdbook build
+  - cp website_config.json book/
 branches:
   only:
-  - master
+    - master

website_config.json

@@ -0,0 +1,10 @@
+{
+  "headers": {
+    "Strict-Transport-Security": "max-age=63072000",
+    "X-Content-Type-Options": "nosniff",
+    "X-Frame-Options": "DENY",
+    "X-XSS-Protection": "1; mode=block",
+    "Referrer-Policy": "no-referrer, strict-origin-when-cross-origin"
+  },
+  "github_pages_origin": "rust-lang.github.io/rust-forge"
+}