Added Dockerfile - #4 [skip ci]

README.md

@@ -29,7 +29,7 @@ Then load it in databases where you want to use it
 CREATE EXTENSION vector;
 ```
 
-You can also install it with [Homebrew](#homebrew) or [PGXN](#pgxn)
+You can also install it with [Docker](#docker), [Homebrew](#homebrew), or [PGXN](#pgxn)
 
 ## Getting Started
 
@@ -140,6 +140,24 @@ Libraries that use pgvector:
 
 ## Additional Installation Methods
 
+### Docker
+
+Get the [Docker image](https://hub.docker.com/repository/docker/ankane/pgvector) with:
+
+```sh
+docker pull ankane/pgvector
+```
+
+This adds pgvector to the [Postgres image](https://hub.docker.com/_/postgres).
+
+You can also build the image manually
+
+```sh
+git clone https://github.com/ankane/pgvector.git
+cd pgvector
+docker build -t pgvector .
+```
+
 ### Homebrew
 
 On Mac with Homebrew Postgres, you can use: