Add create-release script

etc/create-release.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+
+find_latest_semver() {
+    # Gets version from package.json
+    echo $(npm pkg get version | sed 's/"//g')
+}
+
+increment_ver() {
+    find_latest_semver | awk -F. -v a="$1" -v b="$2" -v c="$3" \
+    '{printf("%d.%d.%d", $1+a, $2+b , $3+c)}'
+}
+
+bump() {
+    # Get versions
+    next_ver="$(increment_ver "$1" "$2" "$3")"
+    latest_ver="$(find_latest_semver)"
+
+    # Set package.json version to next version and commit
+    echo "Bumping version to $next_ver"
+    npm pkg set version=$next_ver
+    git add .
+    git commit -m "Bump version to $next_ver"
+
+
+    # Get commits
+    latest_commit=$(git rev-parse "v${latest_ver}" 2>/dev/null )
+    head_commit=$(git rev-parse HEAD)
+
+    # Tag commits
+    if [ "$latest_commit" = "$head_commit" ]; then
+        echo "refusing to tag; $latest_ver already tagged for HEAD ($head_commit)"
+    else
+        echo "tagging v$next_ver $head_commit"
+        git tag "v$next_ver" $head_commit
+    fi
+}
+
+usage() {
+    echo "Pass a bump type: major|minor|patch"
+    exit 1
+}
+
+case $1 in
+    major) bump 1 0 0;;
+    minor) bump 0 1 0;;
+    patch) bump 0 0 1;;
+    *) usage
+esac