Fixed build.sh

This patch fixes passing the branch to the build script

docker/build.sh

@@ -11,8 +11,10 @@ cat << EOF
 usage: $0 options
 
 OPTIONS:
+   -h      Show help
    -t      The tag/version (${TAG}) (default = master)
    -d      Use Dockerfile-dev for a git clone build
+   -b      Branch to use (default = master)
 EOF
 }
 
@@ -20,9 +22,9 @@ EOF
 ALL_PLATFORMS=0
 DEV=0
 TAG="latest"
-BRANCH="master"
+BRANCH=${BRANCH:-master}
 
-while getopts “t:dab:” OPTION
+while getopts “hdat:b:” OPTION
 do
     case $OPTION in
         t)
@@ -37,9 +39,13 @@ do
         d)
            DEV=1
            ;;
+        h)
+           usage
+           exit 0
+           ;;
         ?)
            usage
-           exit
+           exit -1
            ;;
     esac
 done
@@ -51,7 +57,7 @@ then
     PLATFORMS="linux/arm/v7,linux/arm64,linux/amd64"
     #PLATFORMS="linux/arm/v7,linux/arm/v6,linux/amd64"
 else
-    PLATFORMS="linux/amd64"
+    PLATFORMS="linux/amd64,linux/arm/v7"
 fi
 
 echo "Build with tag=${TAG} BRANCH=${BRANCH} dev?=${DEV} platforms?=${PLATFORMS}"