Added showing release notes while upgrading

Author: krom

CHANGELOG.md

@@ -1,3 +1,5 @@
+* Added showing release notes while upgrading
+
 ## 1.0.1 (2018-06-06)
 * Added Makefile.sample.mk
 * Added CHANGELOG.md

README.md

@@ -39,7 +39,7 @@ USAGE
 SAMPLES
 -------
 
-Basic command (you can copy and paste it into your Makefile)
+Basic commands (you can copy and paste it into your Makefile)
 
 ```makefile
 up: ## Start all or c=<name> containers in foreground

src/self-upgrade.sh

@@ -1,15 +1,28 @@
 #!/usr/bin/env sh
+# Get some property from release
+# Usage:
+#   get_latest_release user/repo tag_name
 get_latest_release() {
   curl --silent "https://api.github.com/repos/$1/releases/latest" | # Get latest release from GitHub api
-    grep '"tag_name":' |                                            # Get tag line
+    grep "\"$2\":" |                                                # Get tag line
     sed -E 's/.*"([^"]+)".*/\1/'                                    # Pluck JSON value
 }
-v=$(get_latest_release $MK_REPO)
 
-if [ $v = $MK_VERSION ]; then
+# Getting last version
+NEW_VER=$(get_latest_release $MK_REPO tag_name)
+
+if [ $NEW_VER = $MK_VERSION ]; then
     echo 'Up to date';
 else
-    echo "A new version is available";
-    echo "Upgrading from $MK_VERSION to $v";
-    curl -sL https://raw.githubusercontent.com/$MK_REPO/master/scripts/upgrade.sh | ( echo "MK_REPO=$MK_REPO; MK_VERSION=$v; "; cat -   ) | sh
+    echo "A new version is available"
+    body=$(get_latest_release $MK_REPO body)
+    echo "Upgrading from $MK_VERSION to $NEW_VER
+
+     Release notes
+************************
+$body
+************************
+";
+    # Downloading and executing upgrade script
+    curl -sL https://raw.githubusercontent.com/$MK_REPO/master/scripts/upgrade.sh | ( echo "MK_REPO=$MK_REPO; MK_VERSION=$NEW_VER; "; cat -   ) | sh
 fi;