Improve instructions for getting started

- Change default command so that users don't try to build all of
crates.io
- Don't mislead users to think that `docker-compose up` will rebuild the
site
- Add instructions for building a sample crate
- Document when and where the server will be ready to access

Author: jyn514

Dockerfile

@@ -74,4 +74,4 @@ COPY docker-entrypoint.sh /opt/docsrs/entrypoint.sh
 
 WORKDIR /opt/docsrs
 ENTRYPOINT ["/opt/docsrs/entrypoint.sh"]
-CMD ["daemon", "--foreground"]
+CMD ["start-web-server"]

README.md

@@ -61,7 +61,20 @@ Make sure you have docker-compose and are able to download ~10GB data on the fir
 git clone https://github.com/rust-lang/docs.rs.git docs.rs
 cd docs.rs
 cp .env.sample .env
-docker-compose up  # This may take a half hour or more on the first run
+
+docker-compose build  # This builds the docs.rs binary
+
+# Build a sample crate to make sure it works
+# This sets up the docs.rs build environment, including installing the nightly
+# Rust toolchain. This will take a while the first time but will be cached afterwards.
+docker-compose run web build crate regex 1.3.1
+
+# This starts the web server but does not build any crates.
+# If you want to build crates, see below under `build` subcommand
+docker-compose up
+
+# As soon as you see `cratesfyi "$@"`
+# you should be able to navigate to http://localhost:3000
 ```
 
 If you need to store big files in the repository's directory it's recommended to