Fix adding dependency to missing section

Issue #61

poetry/console/commands/add.py

@@ -54,6 +54,9 @@ If you do not specify a version constraint, poetry will choose a suitable one ba
         content = self.poetry.file.read()
         content = self.poetry.file.read()
         poetry_content = content["tool"]["poetry"]
         poetry_content = content["tool"]["poetry"]
 
 
+        if section not in poetry_content:
+            poetry_content[section] = {}
+
         for name in packages:
         for name in packages:
             for key in poetry_content[section]:
             for key in poetry_content[section]:
                 if key.lower() == name.lower():
                 if key.lower() == name.lower():

tests/console/commands/test_add.py

@@ -382,3 +382,38 @@ Writing lock file
         "version": "0.2.0",
         "version": "0.2.0",
         "platform": platform,
         "platform": platform,
     }
     }
+
+
+def test_add_to_section_that_does_no_exist_yet(app, repo, installer):
+    command = app.find("add")
+    tester = CommandTester(command)
+
+    repo.add_package(get_package("cachy", "0.1.0"))
+    repo.add_package(get_package("cachy", "0.2.0"))
+
+    tester.execute(
+        [("command", command.get_name()), ("name", ["cachy"]), ("--dev", True)]
+    )
+
+    expected = """\
+Using version ^0.2.0 for cachy
+
+Updating dependencies
+Resolving dependencies...
+
+
+Package operations: 1 install, 0 updates, 0 removals
+
+Writing lock file
+
+  - Installing cachy (0.2.0)
+"""
+
+    assert tester.get_display(True) == expected
+
+    assert len(installer.installs) == 1
+
+    content = app.poetry.file.read()["tool"]["poetry"]
+
+    assert "cachy" in content["dev-dependencies"]
+    assert content["dev-dependencies"]["cachy"] == "^0.2.0"

tests/fixtures/simple_project/pyproject.toml

@@ -23,5 +23,3 @@ classifiers = [
 # Requirements
 # Requirements
 [tool.poetry.dependencies]
 [tool.poetry.dependencies]
 python = "~2.7 || ^3.6"
 python = "~2.7 || ^3.6"
-
-[tool.poetry.dev-dependencies]