ADD: standalone Dockerfile and gitlab-ci integration

.gitlab-ci.yml

+stages:
+  - test
+
+test:
+  stage: test
+  image: czen/ubuntu_xbuild
+  script:
+    - ./prebuild.sh
+    - ./build.sh
+    - ./run_tests.sh
+  tags:
+    - docker
+  
+grade:
+  stage: grade
+  image: czen/ubuntu_xbuild
+  script:
+    - ./prebuild.sh
+    - ./build.sh
+    - ./grade.sh
+  only:
+    - master
+  tags:
+    - docker

Dockerfile

+#FROM gitpod/workspace-dotnet
+FROM ubuntu:latest
+
+RUN apt-get update &&  apt install -y nuget mono-devel mono-xbuild
+RUN nuget update -self
+RUN mkdir /compilers
+
+WORKDIR /compilers
\ No newline at end of file

grade.sh

+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestSimpleLexer/bin/Debug/TestSimpleLexer.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestLexer/bin/Debug/TestLexer.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestGeneratedLexer/bin/Debug/TestGeneratedLexer.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestDescentParser/bin/Debug/TestDescentParser.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestGeneratedParser/bin/Debug/TestGeneratedParser.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestASTParser/bin/Debug/TestASTParser.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestVisitors/bin/Debug/TestVisitors.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
+ mono packages/NUnit.ConsoleRunner.3.10.0/tools/nunit3-console.exe --labels=ON TestCodeGenerator/bin/Debug/TestCodeGenerator.dll
+ mono NunitReportParser/bin/Debug/NunitReportParser.exe ${TRAVIS_BUILD_DIR} ${TRAVIS_REPO_SLUG}
\ No newline at end of file

prebuild.sh

+#!/bin/bash
+nuget restore Compilers.sln
\ No newline at end of file