Move test reporter configuration to circleCI

Installing it is superfast and upgrading here is easier.

.circleci/config.yml

@@ -6,6 +6,12 @@ steps: &steps
   steps:
     - checkout
 
+    - run:
+        name: Install coverage reporter
+        command: |
+          curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > cc-test-reporter
+          chmod +x cc-test-reporter
+
     - restore_cache:
         keys:
           - dependencies-{{ checksum "Gemfile.lock" }}

docker/Dockerfile

@@ -62,8 +62,4 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 ENV BUNDLE_SILENCE_ROOT_WARNING=1
 
-RUN TEST_REPORTER_URL=https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 \
-  && wget -O /usr/local/bin/cc-test-reporter $TEST_REPORTER_URL \
-  && chmod +x /usr/local/bin/cc-test-reporter
-
 WORKDIR /byebug