Remove redundant installation steps [skip ci] (#1148)

I feel like this instruction is redundant due to the presence of
63acd40521/bin/setup (L22)

README.md

@@ -152,10 +152,7 @@ This section provides a high-level requirement & quick start guide. For detailed
 0.  Make sure all the prerequisites are installed.
 1.  Fork dev.to repository, ie. https://github.com/thepracticaldev/dev.to/fork
 1.  Clone your forked repository, ie. `git clone https://github.com/<your-username>/dev.to.git`
-1.  `gem install bundler`
 1.  `gem install foreman`
-1.  `bundle install`
-1.  `bin/yarn`
 1.  Setup your database
     - Create `config/database.yml` by copying from the provided template (i.e. `cp config/database.yml.sample config/database.yml`)
     - Update the `config/database.yml` file if needed.