Replaced selected docs references to ADD with COPY

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)

docs/sources/articles/baseimages.md

@@ -52,7 +52,7 @@ which you can `docker pull`. You can then use that
 image to base your new minimal containers `FROM`:
 
     FROM scratch
-    ADD true-asm /true
+    COPY true-asm /true
     CMD ["/true"]
 
 The Dockerfile above is from extremely minimal image - [tianon/true](

docs/sources/articles/using_supervisord.md

@@ -52,7 +52,7 @@ Now let's add a configuration file for Supervisor. The default file is
 called `supervisord.conf` and is located in
 `/etc/supervisor/conf.d/`.
 
-    ADD supervisord.conf /etc/supervisor/conf.d/supervisord.conf
+    COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf
 
 Let's see what is inside our `supervisord.conf`
 file.

docs/sources/examples/nodejs_web_app.md

@@ -84,11 +84,11 @@ via-package-manager#rhelcentosscientific-linux-6):
     # Install Node.js and npm
     RUN     yum install -y npm
 
-To bundle your app's source code inside the Docker image, use the `ADD`
+To bundle your app's source code inside the Docker image, use the `COPY`
 instruction:
 
     # Bundle app source
-    ADD . /src
+    COPY . /src
 
 Install your app dependencies using the `npm` binary:
 
@@ -117,7 +117,7 @@ Your `Dockerfile` should now look like this:
     RUN     yum install -y npm
 
     # Bundle app source
-    ADD . /src
+    COPY . /src
     # Install app dependencies
     RUN cd /src; npm install
 

docs/sources/examples/running_riak_service.md

@@ -53,7 +53,7 @@ After that, we install and setup a few dependencies:
 
     RUN locale-gen en_US en_US.UTF-8
 
-    ADD supervisord.conf /etc/supervisor/conf.d/supervisord.conf
+    COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf
 
     RUN echo 'root:basho' | chpasswd