Referring to the link: [[https://www.openproject.org/development/setting-up-development-environment/]]
I was setting up development environment in ubuntu 16, gnome-terminal. But it fails in the following step.
@ ./bin/rake db:migrate db:seed db:test:prepare@
I get the following error message:

Traceback (most recent call last):
    4: from ./bin/rake:2:in `<main>'
    3: from ./bin/rake:2:in `require_relative'
    2: from /home/tanzeem/openproject-dev/openproject/config/boot.rb:39:in `<top (required)>'
    1: from /home/tanzeem/.rvm/rubies/ruby-2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
/home/tanzeem/.rvm/rubies/ruby-2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': cannot load such file -- bundler/setup (LoadError)

Whe I added sudo to the command
sudo ./bin/rake db:migrate db:seed db:test:prepare
I get the following message in red color
Your Ruby version is 2.3.1, but your Gemfile specified ~> 2.5.1
Following the error message I tried rvm list
and got the following output

=* ruby-2.5.1 [ x86_64 ]

# => - current
# =* - current && default
#  * - default

Trying the commands
rvm use ruby-2.5.1

Using /home/tanzeem/.rvm/gems/ruby-2.5.1

and
ruby -v
gave the following result:

ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]

But
sudo ./bin/rake db:migrate db:seed db:test:prepare still gets the same error in red:
Your Ruby version is 2.3.1, but your Gemfile specified ~> 2.5.1

Please help me to move further in completing the installation.