+ update composer bash helper script

* preventing create symlinks if symlink has exists

create-symlinks.sh

@@ -6,5 +6,10 @@ BASH_SCRIPTS_DIR="${DIR}/bash"
 BASH_SCRIPTS=(`ls $BASH_SCRIPTS_DIR`)
 
 for FILENAME in "${BASH_SCRIPTS[@]}"; do
-  ln -s ${BASH_SCRIPTS_DIR}/${FILENAME} ${HOME}/
+  BASH_SCRIPT_FILE_PATH="${BASH_SCRIPTS_DIR}/${FILENAME}"
+  SYMLINK_PATH="${HOME}/${FILENAME}"
+
+  if [[ ! -f "${SYMLINK_PATH}" ]]; then
+    ln -s "${BASH_SCRIPT_FILE_PATH}" "${SYMLINK_PATH}"
+  fi
 done