Update webapp/nickserver repo on deploy

before deploy:

leap-webapp@elephant:~$ git status
On branch develop
Your branch is behind 'origin/develop' by 21 commits, and can be fast-forwarded.
  (use "git pull" to update your local branch)
nothing to commit, working directory clean

after deploy:

leap-webapp@elephant:~$ git status
On branch develop
Your branch is behind 'origin/develop' by 21 commits, and can be fast-forwarded.
  (use "git pull" to update your local branch)
Changes not staged for commit:
  (use "git add/rm ..." to update what will be committed)
  (use "git checkout -- ..." to discard changes in working directory)

        modified:   Gemfile.lock
        deleted:    config/customization/.gitkeep

no changes added to commit (use "git add" and/or "git commit -a")

a manual git pull succeeded without problems:

leap-webapp@elephant:~$ git pull
Updating 4a73c2c..e3158f5
Fast-forward
 app/assets/images/{Twitter_Logo_Blue.png => Avatar_Pic.png} | Bin
 app/assets/stylesheets/twitter.scss                         |   1 +
 app/helpers/twitter_helper.rb                               |  36 +++++++++++++++++++++++++++++++++++-
 app/views/home/_content.html.haml                           |  24 +++++++++++++++++-------
 app/views/twitter/_index.html.erb                           |  19 ++++++++++---------
 config/initializers/assets.rb                               |   1 +
 config/initializers/customization.rb                        |   4 +---
 doc/TWITTER_FEED.md                                         |  22 ++++++++++++++++++++--
 script/generate_bearer_token                                |   6 ++++--
 9 files changed, 89 insertions(+), 24 deletions(-)
 rename app/assets/images/{Twitter_Logo_Blue.png => Avatar_Pic.png} (100%)
 create mode 100644 config/initializers/assets.rb
leap-webapp@elephant:~$ git status
On branch develop
Your branch is up-to-date with 'origin/develop'.
Changes not staged for commit:
  (use "git add/rm ..." to update what will be committed)
  (use "git checkout -- ..." to discard changes in working directory)

        modified:   Gemfile.lock
        deleted:    config/customization/.gitkeep

no changes added to commit (use "git add" and/or "git commit -a")

I stepped into this while debugging the webapp, maybe this is the same for all vcsrepos ?

(from redmine: created on 2016-09-28)