add Makefile as documentation

Signed-off-by: Michael Leuschel <leuschel@uni-duesseldorf.de>

Makefile

+# Makefile as documentation on how to build the TLA2B.jar file
+# This file should then appear in ProB's lib folder
+# This file is for documentation, for user's not familiar with gradle
+build/libs/TLA2B.jar: src/main/java/de/tla2b/*/*.java src/main/java/de/tla2b/*.java src/main/java/de/tla2bAst/*.java build.gradle
+	@echo "Building TLA2B.jar"
+	gradle shadowJar
+install: build/libs/TLA2B.jar
+	@echo "Copying the TLA2B jar file to default location of prob_prolog"
+	cp build/libs/TLA2B.jar ../../prob_prolog/lib/
+FILE = src/test/resources/examples/instance/Counter/Counter
+test: build/libs/TLA2B.jar
+	@echo "Running a simple test using the TLA2B jar file"
+	java -jar build/libs/TLA2B.jar $(FILE).tla
+	@echo "Checking if probcli can load the generate .prob file"
+	probcli $(FILE).prob -ppf user_output