Detect if Raspbian Linux and patch docker installation script (#176)

btcpay-setup.sh

@@ -358,13 +358,20 @@ if ! [[ -x "$(command -v docker)" ]] || ! [[ -x "$(command -v docker-compose)" ]
         			brew install docker
         			brew link docker
         		fi
-        	else
-        		# Not Mac OS
-				echo "Trying to install docker..."
-				curl -fsSL https://get.docker.com -o get-docker.sh
-				chmod +x get-docker.sh
-				sh get-docker.sh
-				rm get-docker.sh
+            elif grep -i raspbian /etc/*-release >/dev/null 2>&1;then
+                # Raspbian Linux
+                echo "Trying to install docker using Raspbian 10 patch..."
+                curl -fsSL https://get.docker.com|sed -e 's/buster/stretch/' > get-docker.sh
+                chmod +x get-docker.sh
+                sh get-docker.sh
+                rm get-docker.sh
+            else
+                # Not Raspbian Linux or Mac OS
+                echo "Trying to install docker..."
+                curl -fsSL https://get.docker.com -o get-docker.sh
+                chmod +x get-docker.sh
+                sh get-docker.sh
+                rm get-docker.sh
             fi
         elif [[ "$(uname -m)" == "aarch64" ]]; then
             echo "Trying to install docker for armv7 on a aarch64 board..."