Create an `rvm` user instead of relying on root for the container.

The `rvm` user has passwordless sudo in the container, so that shouldn't slow
anybody down :)

Dockerfile

@@ -3,7 +3,12 @@ FROM ubuntu:trusty
 # Grab the bare necessities for installing RVM and some Rubies
 RUN apt-get update && \
     apt-get install -yq git build-essential curl gnupg && \
-    gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 && \
+    useradd -c "RVM User" -d /home/rvm -G sudo -s /bin/bash -m rvm
+
+USER rvm
+
+RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 && \
     curl -sSL https://get.rvm.io | bash -s stable
 
-COPY rvmrc /root/.rvmrc
+COPY sudoers /etc/sudoers.d/10-sudo-nopasswd
+COPY rvmrc /home/rvm/.rvmrc

build-rubies.sh

@@ -11,7 +11,7 @@ for RUBY in "${RUBIES[@]}"; do
     cat > $DOCKERFILE <<EOF
 FROM ${IMAGE_TAG}:latest
 
-RUN bash -c 'source /usr/local/rvm/scripts/rvm && rvm install ${RUBY}'
+RUN bash -c 'source ~/.rvm/scripts/rvm && rvm install ${RUBY}'
 EOF
 
     echo "> Making ${IMAGE_TAG}:${RUBY}"

sudoers

@@ -0,0 +1 @@
+%sudo  ALL=(ALL) NOPASSWD: ALL