improve readme

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     - uses: actions/checkout@v1
 
     - name: Set up Postgresql with Postgis
-      uses: huaxk/postgis-action@master
+      uses: huaxk/postgis-action@v1
       with:
         postgresql user: 'test'
         postgresql password: ${{ secrets.DatabasePassword }}

README.md

@@ -1,2 +1,26 @@
-# postgis-action
-GitHub Action to setup a PostgreSQL database with Postgis.
+# PostgreSQL with Postgis GitHub Action
+This [GitHub Action](https://github.com/features/actions) setup a PostgreSQL database with Postgis.
+
+# Usage
+
+Basic:
+```yaml
+steps:
+- uses: huaxk/postgis-action@v1
+  with:
+    postgresql version: '11'  # See https://https://hub.docker.com/r/mdillon/postgis for available versions, if it is not specified, use the default value 'latest'
+    postgresql password: ${{ secrets.DatabasePassword }}   # This environment variable sets the superuser password for PostgreSQL, maybe string or secrets, the default superuser is defined by the input environment variable: postgresql user.
+    postgresql user: 'test'  # This optional environment variable is used in conjunction with postgresql password to set a user and its password. This variable will create the specified user with superuser power and a database with the same name. If it is not specified, then the default user of 'postgres' will be used.
+    postgresql db: 'test'  # This optional environment variable can be used to define a different name for the default database that is created when the image is first started. If it is not specified, then the value of postgresql user will be used.
+```
+
+Clinet params:
+* host: "localhost"
+* user: "test"
+* password: ***
+* database: "test"
+* port: 5432
+
+# License
+
+The scripts and documentation in this project are released under the [MIT License](LICENSE)