Try to optimize image size

Dockerfile

@@ -10,24 +10,12 @@ ENV RAILS_ENV=$RAILS_ENV_ARG
 ENV RAILS_ROOT /var/www/texterify
 
 # Install essential libraries.
-RUN apt-get update && apt-get install -y build-essential libpq-dev
+RUN apt-get update && apt-get install -y build-essential libpq-dev curl apt-transport-https yarn && apt-get -y autoclean
 
 # Set workdir.
 RUN mkdir -p $RAILS_ROOT
 WORKDIR $RAILS_ROOT
 
-# Install gems.
-COPY Gemfile Gemfile
-COPY Gemfile.lock Gemfile.lock
-RUN gem install bundler:2.1.4
-RUN bundle install --jobs 20 --retry 5 --without development test
-
-# Update the repository sources list
-# and install dependencies.
-RUN apt-get update \
-    && apt-get install -y curl \
-    && apt-get -y autoclean
-
 # Install nvm.
 ENV NVM_DIR /usr/local/nvm
 RUN mkdir -p $NVM_DIR
@@ -47,10 +35,14 @@ ENV NODE_PATH $NVM_DIR/v$NODE_VERSION/lib/node_modules
 ENV PATH $NVM_DIR/versions/node/v$NODE_VERSION/bin:$PATH
 
 # Install yarn.
-RUN apt-get install apt-transport-https
 RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
 RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
-RUN apt-get update && apt-get install yarn -y
+
+# Install gems.
+COPY Gemfile Gemfile
+COPY Gemfile.lock Gemfile.lock
+RUN gem install bundler:2.1.4
+RUN bundle install --jobs 20 --retry 5 --without development test
 
 # Copy project files.
 COPY . .