Update README.md

Clarification of git tag or docker image tag.
Typo.

README.md

@@ -31,7 +31,7 @@ A git tag will typically look like this.
 
 ### Docker image tag
 
-This repository uses docker hub autobuild and derives many image tags from one build. A build from `1.15.2-6` will thus create the following tags:
+This repository uses docker hub autobuild and derives many image tags from one build. A docker hub build from git tag `1.15.2-6` will thus create the following docker image tags:
 
 1. `1.15.2`
 1. `1.15.2-6`
@@ -40,6 +40,6 @@ This repository uses docker hub autobuild and derives many image tags from one b
 1. `1.15.2-ubuntu.18.10`
 1. `1.15.2-ubuntu.18.10-6`
 
-Choosing the right version to base your derived image on depends on your need for stability. If you reliably need to depend on the correct version of Ubuntu, use a tag such as `1.15.2-ubuntu.18.10`. If you reliably need to depend on a certain revision from within this repository, but the operating system is irrelevant, us a tag such as `1.15.2-6`.
+Choosing the right version to base your derived image on depends on your need for stability. If you reliably need to depend on the correct version of Ubuntu, use a tag such as `1.15.2-ubuntu.18.10`. If you reliably need to depend on a certain revision from within this repository, but the operating system is irrelevant, use a tag such as `1.15.2-6`.
 
-[pre-commit]: https://pre-commit.com
+[pre-commit]: https://pre-commit.com