script: Added support for Mac user for using docker compose script

bin/docker-compose

@@ -1,9 +1,63 @@
 #!/bin/sh
 
-command -v docker-compose >/dev/null 2>&1 || { echo >&2 "ERROR: Please install docker-compose."; exit 1; }
+# Subfunction: Checks the rquirements
+check_requirement() {
+    command -v $1 >/dev/null 2>&1 || fatal "\
+$1 is not available on your system.
+Please install it and try again. Good bye and hope we see you soon!"
+}
 
-WORKDIR=$(dirname $(readlink -f $0))/../
+# Subfunction: Print out the Error message
+fatal() {
+    echo >&2 "ERROR: $*"
+    exit 1
+}
 
+# Check if following packages are installed:
+#   -) docker-compose
+#   -) on Linux: readlink
+#   -) on Darwin(Mac): greadlink
+check_requirement docker-compose
+check_requirement readlink || check_requirement greadlink
+
+# Store the command for detecting the OS (operating system)
+# [Host: command output]; Linux: Linux; Mac: Darwin
+unameOut="$(uname -s)"
+
+# Comment for future tasks - Include other operating systems
+# ==> these OS checks can be included in the case-esac statement and mybe some other changes are requiered
+# CYGWIN*)    machine=Cygwin;;  Another OS => currently not supported;
+#       Translater to run GNU/Linux, BSD, and Unix programms on Windows
+# MINGW*)     machine=MinGw;;   Another OS => currently not supported;
+#       open source software development environment to create Microsoft Windows applications
+
+# Detect the OS
+case "${unameOut}" in
+                # Supported OS
+    Linux*)     OS=Linux;;
+    Darwin*)    OS=Darwin;;
+
+                # The OS is not supported. Give feedback and terminate with error
+    *)          fatal "You are not working on a supported OS! Currently ShellHub supports Linux and Darwin(Mac)."
+esac
+
+# OS is already checked before in the case statement -> as of now the OS is supported
+echo "You are working on a supported OS! Happy dockering!"
+echo "Your OS is: " ${OS}
+
+# Set the appropriate working directories for the specific OS
+# Supported Linux OS
+if [ $OS == 'Linux' ]
+then
+    WORKDIR=$(dirname $(readlink -f $0))/../
+fi
+# Supported Darwin (Mac) OS
+if [ $OS == 'Darwin' ]
+then
+    WORKDIR=$(dirname $(greadlink -f $0))/../
+fi
+
+# Change to working directory
 cd $WORKDIR
 
 set -o allexport