Add support to install script to install BeEF on OpenBSD.

The tricky part is that on OpenBSD, there might be multiple
Ruby versions available in parallel. They are, and the binaries
using each of thse version, suffixed with the version number.
Therefore add a global variable RUBYSUFFIX default to empty,
and when detecting OpenBSD add this suffix to all Ruby commands
from the script.

Also add a simple install_openbsd function just installing
all the system packages.

run the script with "bash install"
and later on run BeEF with "ruby24 beef"

install

@@ -13,6 +13,7 @@ info()  { echo -e "\\033[1;36m[INFO]\\033[0m  $*"; }
 warn()  { echo -e "\\033[1;33m[WARNING]\\033[0m  $*"; }
 fatal() { echo -e "\\033[1;31m[FATAL]\\033[0m  $*"; exit 1 ; }
 
+RUBYSUFFIX=''
 
 command_exists () {
 
@@ -44,6 +45,17 @@ check_os () {
   elif [ "${OS}" = "Darwin" ]; then
     info "Launching Mac OSX install..."
     install_mac
+  elif [ "${OS}" = "OpenBSD" ]; then
+    info "Launching OpenBSD install..."
+    for SUFX in 26 25 24 23
+    do
+      if command_exists ruby${SUFX}
+      then
+        RUBYSUFFIX=${SUFX}
+        break
+      fi
+    done
+    install_openbsd
   else
     fatal "Unable to locate installer for your Operating system: $OS"
   fi
@@ -81,6 +93,11 @@ install_linux () {
   fi
 }
 
+install_openbsd () {
+
+  sudo pkg_add curl git libyaml libxml libxslt bison node ruby${RUBYSUFFIX}-bundler lame espeak
+
+}
 
 install_mac () {
   # brew install ...
@@ -93,11 +110,11 @@ check_ruby_version () {
   info 'Detecting Ruby environment...'
 
   MIN_RUBY_VER='2.3'
-  if command_exists ruby
+  if command_exists ruby${RUBYSUFFIX}
   then
-    RUBY_VERSION=$(ruby -e "puts RUBY_VERSION")
+    RUBY_VERSION=$(ruby${RUBYSUFFIX} -e "puts RUBY_VERSION")
     info "Ruby version ${RUBY_VERSION} is installed"
-    if [ "$(ruby -e "puts RUBY_VERSION.to_f >= ${MIN_RUBY_VER}")" = 'false' ]
+    if [ "$(ruby${RUBYSUFFIX} -e "puts RUBY_VERSION.to_f >= ${MIN_RUBY_VER}")" = 'false' ]
     then
       fatal "Ruby version ${RUBY_VERSION} is not supported. Please install Ruby ${MIN_RUBY_VER} (or newer) and restart the installer."
     fi
@@ -111,12 +128,12 @@ check_bundler () {
 
   info 'Detecting bundler gem...'
   
-  if command_exists bundler
+  if command_exists bundler${RUBYSUFFIX}
   then
-    info 'bundler gem is installed'
+    info "bundler${RUBYSUFFIX} gem is installed"
   else
     info 'Installing bundler gem'
-    gem install bundler
+    gem${RUBYSUFFIX} install bundler
   fi
 }
 
@@ -124,7 +141,7 @@ check_bundler () {
 install_beef () { 
 
   echo "Installing required Ruby gems..."
-  bundle install --without test development
+  bundle${RUBYSUFFIX} install --without test development
 
   echo
   echo "=========================================="