describe versioning in readme and add changelog

CHANGELOG.md

@@ -0,0 +1,7 @@
+# Changelog
+
+## v1_db23_p0
+
+**2018-12-18**
+
+* This is the first official release of the SourcetrailDB project.

README.md

@@ -3,6 +3,7 @@
 ## CI Pipelines
 
 Windows Builds: [![Build status](https://ci.appveyor.com/api/projects/status/gbblx1l790vm952c/branch/master?svg=true)](https://ci.appveyor.com/project/mlangkabel/sourcetraildb/branch/master)
+
 Linux and Mac Builds: [![Build Status](https://travis-ci.org/CoatiSoftware/SourcetrailDB.svg?branch=master)](https://travis-ci.org/CoatiSoftware/SourcetrailDB)
 
 ## Introduction
@@ -23,6 +24,16 @@ Note that even though the core of this project is written in C++, this does __no
 If the language of your choice is not covered by this list, feel free to open an issue on the [issue tracker](https://github.com/CoatiSoftware/SourcetrailDB/issues) or even better: join us in our efforts on this project and provide a pull request!
 
 
+## Versioning
+
+The SourcetrailDB version format consists of three numbers and looks like this `vXX_dbYY_pZZ`. 
+* `XX` marks the interface version of the API. This version is increases on every change that breaks backwards compatibility of the API.
+* `YY` marks the version of the database that will be generated when using the SourcetrailDB API. This version needs to match the database version of the Sourcetrail instance that is used to open the generated database file to be compatible. 
+* `ZZ` marks the patch number of the build. It will increase with every release that publishes bugfixes and features that don't break any compatibility.
+
+You can find a complete list of available releases on the [GitHub release page](https://github.com/CoatiSoftware/SourcetrailDB/releases). If you are interested in the actual changes of every release, please take a look at the [Changelog](https://github.com/CoatiSoftware/SourcetrailDB/blob/master/CHANGELOG.md).
+
+
 ## Writing to the Sourcetrail Database
 
 The SourcetrailDB tries to keep the API for writing to the Sourcetrail database as simple as possible. For the C++ core take a look at the list of methods of the [SourcetrailDBWriter](https://github.com/CoatiSoftware/SourcetrailDB/blob/master/core/include/SourcetrailDBWriter.h) class for a complete overview of the provided write API. If you are using bindings for other languages, the code may look different but the set of provided functionality should stay the same. For now, let's jump right into action with some examples!

core/include/SourcetrailDBWriter.h

@@ -52,15 +52,15 @@ namespace sourcetrail
 		SourcetrailDBWriter();
 
 		/**
-		 * Provides the version of the SourcetrailDB Core as string with format "v1_db20_p0"
+		 * Provides the version of the SourcetrailDB Core as string with format "vXX_dbYY_pZZ"
 		 *
-		 * The first number (e.g. "v1") of the version string denotes the interface version of the
-		 * API. This version is increases on change that breaks the backwards compatibility.
-		 * The second number (e.g. "db20") of the version string denotes the version of the database
-		 * that will be generated by this class. This version needs to match the database version of
-		 * the used Sourcetrail version to be compatible.
-		 * The third number (e.g. "p0") is the patch number of the build and will increase with
-		 * release that delivers bugfixes and features that don't break any compatibility.
+		 *  - "XX" marks the interface version of the API. This version is increases on every change
+		 *    that breaks backwards compatibility of the API.
+		 *  - "YY" marks the version of the database that will be generated when using the
+		 *    SourcetrailDB API. This version needs to match the database version of the Sourcetrail
+		 *    instance that is used to open the generated database file to be compatible.
+		 *  - "ZZ" marks the patch number of the build. It will increase with every release that
+		 *    publishes bugfixes and features that don't break any compatibility.
 		 */
 		std::string getVersionString() const;