Added pipeline configuration

.gitlab-ci.yml

+image: golang:1.12.6
+
+variables:
+  REPO: git.fh-muenster.de
+  GROUP: winfo-fse-ss22
+  PROJECT: fermat-primality-test
+
+stages:
+ - test
+
+before_script:
+  - mkdir -p $GOPATH/src/$REPO/$GROUP $GOPATH/src/_/builds
+  - cp -r $CI_PROJECT_DIR $GOPATH/src/$REPO/$GROUP/$PROJECT
+  - ln -s $GOPATH/src/$REPO/$GROUP $GOPATH/src/_/builds/$GROUP
+  - go get -v -d ./...
+
+unit_tests:
+  stage: test
+  script:
+    - go test -v ./... -coverprofile .testCoverage.txt
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