add alpine variant for node v0.12

0.12/alpine/Dockerfile

@@ -0,0 +1,45 @@
+FROM alpine:3.4
+
+ENV NPM_CONFIG_LOGLEVEL info
+ENV NODE_VERSION 0.12.17
+
+RUN adduser -D -u 1000 node \
+    && apk add --no-cache \
+        libstdc++ \
+    && apk add --no-cache --virtual .build-deps \
+        binutils-gold \
+        curl \
+        g++ \
+        gcc \
+        gnupg \
+        libgcc \
+        linux-headers \
+        make \
+        python \
+  && for key in \
+    9554F04D7259F04124DE6B476D5A82AC7E37093B \
+    94AE36675C464D64BAFA68DD7434390BDBE9B9C5 \
+    0034A06D9D9B0064CE8ADF6BF1747F4AD2306D93 \
+    FD3A5288F042B6850C66B31F09FE44734EB7990E \
+    71DCFD284A79C3B38668286BC97EC7A07EDE3FC1 \
+    DD8F2338BAE7501E3DD5AC78C273792F7D83545D \
+    B9AE9905FFD7803F25714661B63B535A4C206CA9 \
+    C4F0DFFF4E8C1A8236409D08E73BC641CC11F4C8 \
+  ; do \
+    gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+  done \
+    && curl -SLO "https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION.tar.xz" \
+    && curl -SLO "https://nodejs.org/dist/v$NODE_VERSION/SHASUMS256.txt.asc" \
+    && gpg --batch --decrypt --output SHASUMS256.txt SHASUMS256.txt.asc \
+    && grep " node-v$NODE_VERSION.tar.xz\$" SHASUMS256.txt | sha256sum -c - \
+    && tar -xf "node-v$NODE_VERSION.tar.xz" \
+    && cd "node-v$NODE_VERSION" \
+    && ./configure \
+    && make -j$(getconf _NPROCESSORS_ONLN) \
+    && make install \
+    && apk del .build-deps \
+    && cd .. \
+    && rm -Rf "node-v$NODE_VERSION" \
+    && rm "node-v$NODE_VERSION.tar.xz" SHASUMS256.txt.asc SHASUMS256.txt
+
+CMD [ "node" ]