Problems Installing Metasploit Framework on Ubuntu - ruby

Question

I have encountered 3 problems while following this guide to installing Metasploit Framework on Ubuntu and Debian:
1) After installing proper version of ruby, there is a command given for installing Ruby libraries: sudo gem install bundler. When I typed that in and hit enter, it says "command not found". After some researching on the internet, I decided to remove sudo and try again. So I've entered gem install bundler and it worked fine. Will this cause any problems?
2) After installing Metasploit Framework, there is a command given to install the required gems and versions:
cd metasploit-framework
bundle install
But when I tried that, I got this error:
rbenv: version '2.1.6' is not installed
I really don't know what to do next (But I moved on).
3) Probably due to the previous problems, in the end when I executed msfconsole command, it said
could not find rake-10.4.2 in any of the sources.
run bundle install to install the missing gems
But the bundle install doesn't help either, because when I run that it says
Could not locate Gemfile or .bundle/directory
Any help would be appreciated.
EDIT: When I asked the person himself who had written the guide, regarding this, he told me to select the version of ruby I had just installed with either rebind or RVM before installing bundler, and then to run the bundle install. Could you please list the commands to do so? I am really new to Linux!

Answer 1

step 1 :
sudo apt-get update
sudo apt-get upgrade
step 2 :
Install dependent packages
sudo apt-get install build-essential libreadline-dev libssl-dev libpq5 libpq-dev libreadline5 libsqlite3-dev libpcap-dev openjdk-7-jre git-core autoconf postgresql pgadmin3 curl zlib1g-dev libxml2-dev libxslt1-dev vncviewer libyaml-dev curl zlib1g-dev
step 3 :
Install Ruby
curl -L https://get.rvm.io | bash -s stable
source ~/.rvm/scripts/rvm
echo "source ~/.rvm/scripts/rvm" >> ~/.bashrc
source ~/.bashrc
rvm install 2.1.6
rvm use 2.1.6 --default
ruby -v
step 4 :
Install and configure postgresql
sudo apt-get install postgresql
sudo -s
su postgres
createuser msf -P -S -R -D
createdb -O msf msf
exit
Step 5 :
Install Metasploit Framework
cd /opt
sudo git clone https://github.com/rapid7/metasploit-framework.git
sudo chown -R `whoami` /opt/metasploit-framework
cd metasploit-framework
cd metasploit-framework
sudo bash -c 'for MSF in $(ls msf*); do ln -s /opt/metasploit-framework/$MSF /usr/local/bin/$MSF;done'
Still if you are facing any issue, you can download the iso or vm image from kali wesbite

Answer 2

I have this problem in kali after install metasploit-framework, and i can't run msfconsole. I solved the problem using the following method:
At change your directory to /usr/share/metasploit-framework:
cd /usr/share/metasploit-framework
and after that, install bundler with gem:
gem install bundler
then:
bundle install
at the end you need to update:
gem update --system
and it will work!

Answer 3

This command fixes it:
apt-get install ruby2.1-dev &&\
apt-get install libsqlite3-dev &&\
bundle install
What it does: install ruby development items