Add alternatives system back in

to allow switching of ruby versions

Author: johnl

debian/ruby2.7.postinst

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+set -e
+
+if [ "$1" = "configure" ]
+then
+        update-alternatives --install /usr/bin/gem gem /usr/bin/gem2.7 181
+        RUBYVER=2.7
+        update-alternatives \
+		--install /usr/bin/ruby ruby /usr/bin/ruby${RUBYVER} 51 \
+        --slave /usr/bin/erb erb /usr/bin/erb${RUBYVER} \
+        --slave /usr/bin/irb irb /usr/bin/irb${RUBYVER} \
+        --slave /usr/bin/rdoc rdoc /usr/bin/rdoc${RUBYVER} \
+        --slave /usr/bin/ri ri /usr/bin/ri${RUBYVER} \
+        --slave /usr/share/man/man1/ruby.1.gz ruby.1.gz /usr/share/man/man1/ruby${RUBYVER}.1.gz \
+        --slave /usr/share/man/man1/erb.1.gz erb.1.gz /usr/share/man/man1/erb${RUBYVER}.1.gz \
+        --slave /usr/share/man/man1/irb.1.gz irb.1.gz /usr/share/man/man1/irb${RUBYVER}.1.gz \
+        --slave /usr/share/man/man1/ri.1.gz ri.1.gz /usr/share/man/man1/ri${RUBYVER}.1.gz
+fi
+#DEBHELPER#

debian/ruby2.7.prerm

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+set -e
+
+if [ "$1" = "remove" ]; then
+        update-alternatives --remove gem /usr/bin/gem2.7
+        update-alternatives --remove ruby /usr/bin/ruby2.7
+fi
+
+#DEBHELPER#