Adds build-base

Dockerfile

@@ -4,6 +4,7 @@ MAINTAINER Nemo <opml.docker@captnemo.in>
 WORKDIR /app
 
 COPY Gemfile Gemfile.lock /app/
+RUN apk add --no-cache build-base
 RUN bundle install
 COPY . /app
 

README.md

@@ -5,3 +5,6 @@ Simple web tool to generate OPML files to let you use RSS feeds everywhere
 Currently only support GitHub Starred Repos: It generates an OPML file so you can follow all of your starred repos easily.
 
 I plan to add more OPML generators: GoodReads feed perhaps?
+
+The canonical URL for this project is https://git.captnemo.in/nemo/opml-gen,
+a [mirror](github.com/captn3m0/opml-gen) is maintained on GitHub.