Europa: integrate core packages, separate universe

Signed-off-by: Solomon Hykes <solomon@dagger.io>

europa-universe/docker/test/bash/bash.cue

@@ -0,0 +1,15 @@
+package docker
+
+cmd: #Command & {
+	script: "echo hello world"
+	exec: {
+		name: "/bin/bash"
+		flags: {
+			"-c":          script
+			"--noprofile": true
+			"--norc":      true
+			"-e":          true
+			"-o":          "pipefail"
+		}
+	}
+}

europa-universe/docker/test/build/build.cue

@@ -0,0 +1,82 @@
+package docker
+
+import (
+	"dagger.io/dagger"
+	"universe.dagger.io/nginx"
+)
+
+build0: #Build & {
+	steps: [
+		{
+			output: #Image & {
+				config: user: "foo"
+			}
+		},
+	]
+}
+
+// Inventory of real-world build use cases
+//
+// 1. Build netlify image
+//    - import alpine base
+//    - execute 'yarn add netlify'
+
+// 2. Build todoapp dev image
+//    - import nginx base
+//    - copy app directory into /usr/share/nginx/html
+
+build2: {
+	source: dagger.#FS
+
+	build: #Build & {
+		steps: [
+			nginx.#Build & {
+				flavor: "alpine"
+			},
+			{
+				// Custom step to watermark the image
+				input:  _
+				output: input & {
+					config: user: "42"
+				}
+			},
+			#Copy & {
+				contents: source
+				dest:     "/usr/share/nginx/html"
+			},
+		]
+	}
+	img: build.output
+
+	// Assert:
+	img: config: user: "42"
+}
+
+// 3. Build alpine base image
+//    - pull from docker hub
+//    - execute 'apk add' once per package
+
+// 4. Build app from dockerfile
+
+// 5. execute several commands in a row
+
+build3: {
+	build: #Build & {
+		steps: [
+			#Pull & {
+				source: "alpine"
+			},
+			#Run & {
+				script: "echo A > /A.txt"
+			},
+			#Run & {
+				script: "echo B > /B.txt"
+			},
+			#Run & {
+				script: "echo C > /C.txt"
+			},
+		]
+	}
+
+	result: build.output
+}