Added Freehold to the projects list in README.

Added a few lines of documentation to clarify that read-only
transactions need to be rolled back and not committed, as per the
discussion in issue #344

2 files changed, 5 insertions, 2 deletions

diff --git a/README.md b/README.md
index 401a757..50f5eee 100644
--- a/README.md
+++ b/README.md
@@ -587,5 +587,6 @@ Below is a list of public, open source projects that use Bolt:
 * [SkyDB](https://github.com/skydb/sky) - Behavioral analytics database.
 * [Seaweed File System](https://github.com/chrislusf/weed-fs) - Highly scalable distributed key~file system with O(1) disk read.
 * [InfluxDB](http://influxdb.com) - Scalable datastore for metrics, events, and real-time analytics.
+* [Freehold](http://tshannon.bitbucket.org/freehold/) - An open, secure, and lightweight platform for your files and data.
 
 If you are using Bolt in a project please send a pull request to add it to the list.
diff --git a/tx.go b/tx.go
index fda6a21..3179c71 100644
--- a/tx.go
+++ b/tx.go
@@ -127,7 +127,8 @@ func (tx *Tx) OnCommit(fn func()) {
 }
 
 // Commit writes all changes to disk and updates the meta page.
-// Returns an error if a disk write error occurs.
+// Returns an error if a disk write error occurs, or if Commit is
+// called on a read-only transaction.
 func (tx *Tx) Commit() error {
 	_assert(!tx.managed, "managed tx commit not allowed")
 	if tx.db == nil {
@@ -203,7 +204,8 @@ func (tx *Tx) Commit() error {
 	return nil
 }
 
-// Rollback closes the transaction and ignores all previous updates.
+// Rollback closes the transaction and ignores all previous updates. Read-only
+// transactions must be rolled back and not committed.
 func (tx *Tx) Rollback() error {
 	_assert(!tx.managed, "managed tx rollback not allowed")
 	if tx.db == nil {