Update README.md

README.md

@@ -1,2 +1,104 @@
 # tumbo
+
 Docker matrix build generator
+
+```yaml
+variables:
+    my_var:
+        - a
+        - b
+        - c
+    some_other:
+        - 0.1.0
+        - 0.1.2
+
+context: ./build
+recipe: './Dockerfile.j2'
+tag: "my-tag:{{ my_var }}-{{ some_other }}"
+
+parallel: no
+# no
+# yes : uses all threads available
+# n : number of threads to use
+# default: yes
+
+push: yes
+run: yes
+registry:
+    username: my_user
+    password: my_pass
+    host: my_host
+```
+
+### Config Reference
+
+#### Variables
+
+The variables to build the matrix. Simply specify an array for each variable. They will be available in the template.
+
+```yaml
+variables:
+    my_var:
+        - a
+        - b
+        - c
+    some_other:
+        - 0.1.0
+        - 0.1.2
+```
+
+#### Recipe
+
+The template to compile the dockerfile. Can be a template itself if you don't want to write everything in the same file.
+
+###### Simple
+
+```yaml
+recipe: './Dockerfile.j2'
+```
+
+###### Template
+
+```yaml
+variables:
+    my_var:
+        - a
+        - b
+
+recipe: './{{ my_var }}.j2'
+```
+
+Assuming `my_var` hast the values `a` and `b` it will render to `./a.j2` and `./b.j2` accordingly.
+
+#### Context (Optional)
+
+**Default:** directory of the config file.
+
+Specify the directory where the templates and the dockerfiles will be built.
+Supports both absolute and relative paths.
+
+```yaml
+context: ./build
+```
+
+#### Tag (Optional)
+
+**Default:** Creates a tag that includes all variables.
+In most cases it will not be necessary to specify, but can be usefull if your are pushing images. Supports templating of course.
+
+**Important:** The tag should be unique across the matrix, otherwise you will overwrite other tags. So always include all the variables you specified inside the image name
+
+```yaml
+variables:
+    var1:
+        - a
+        - b
+    var2:
+        - a
+        - b
+    var3:
+        - a
+        - b
+
+tag: 'my-image-name:{{ var3 }}-{{ var1 }}-{{ var2 }}'
+```