Use Jinja syntax.

playbooks/roles/edxapp/handlers/main.yml

@@ -11,14 +11,14 @@
 
 # Ruby plays that need to be run after platform updates.
 - name: gem | gem install bundler
-  shell: RBENV_ROOT=${rbenv_root} GEM_HOME=${gem_home} ${rbenv_root}/shims/gem install bundle chdir=${platform_code_dir}
+  shell: RBENV_ROOT={{ rbenv_root }} GEM_HOME={{ gem_home }} {{ rbenv_root }}/shims/gem install bundle chdir={{ platform_code_dir }}
   tags:
   - ruby
   - deploy
   - install
 
 - name: bundle | bundle install
-  shell: RBENV_ROOT=${rbenv_root} GEM_HOME=${gem_home} ${gem_home}/bin/bundle install --binstubs chdir=${platform_code_dir}
+  shell: RBENV_ROOT={{ rbenv_root }} GEM_HOME={{ gem_home }} {{ gem_home }}/bin/bundle install --binstubs chdir={{ platform_code_dir }}
   tags:
   - ruby
   - deploy
@@ -26,7 +26,7 @@
 
 # Node play that need to be run after platform updates.
 - name: Install edx-platform npm dependencies
-  shell: npm install chdir=${platform_code_dir}
+  shell: npm install chdir={{ platform_code_dir }}
   tags:
   - npm
   - update