[CI] Simplifies Dockerfile

We don't need to create snapshots anymore, so removing unnecessary
user configuration.

Author: picandocodigo

.buildkite/Dockerfile

@@ -2,35 +2,16 @@ ARG RUBY_VERSION=${RUBY_VERSION:-3.1}
 ARG RUBY_SOURCE=${RUBY_SOURCE:-ruby}
 FROM $RUBY_SOURCE:$RUBY_VERSION
 
-# Default UID/GID to 1000
-# it can be overridden at build time
-ARG BUILDER_UID=1000
-ARG BUILDER_GID=1000
-ENV BUILDER_USER elastic
-ENV BUILDER_GROUP elastic
-
 ARG QUIET=${QUIET:-true}
 ARG CI=${CI:-false}
 ENV QUIET=$QUIET
 ENV CI=$CI
 ARG TRANSPORT_VERSION=${TRANSPORT_VERSION:-8}
 
 # Install required tools
-RUN apt-get -q update \
-    && apt-get -y install zip curl git
-
-# Create user
-RUN groupadd --system -g ${BUILDER_GID} ${BUILDER_GROUP} \
-    && useradd --system --shell /bin/bash -u ${BUILDER_UID} -g ${BUILDER_GROUP} -d /var/lib/elastic -m elastic 1>/dev/null 2>/dev/null \
-    && mkdir -p /usr/src/app && touch /Gemfile.lock \
-    && chown -R ${BUILDER_USER}:${BUILDER_GROUP} /usr/src/app /Gemfile.lock
-
-COPY --chown=$BUILDER_USER:$BUILDER_GROUP . .
-
+RUN apt-get -q update && apt-get -y install zip curl git
 WORKDIR /usr/src/app
-
-USER ${BUILDER_USER}:${BUILDER_GROUP}
-
+COPY . .
 RUN bundle install \
     && bundle exec rake bundle:clean \
     && rake bundle:install